This page discusses the several transportation options between Santa Cruz and San Francisco, then discusses more specific cases where you want to get to a particular location at either end, or to the airports. Finally, I will mention the San Francisco Opera (which is why I usually want to go to the city). If you were looking for an opera company in the Santa Cruz area, then you probably mean the Bay Shore Lyric Opera in Capitola. Also, the UCSC music department occasionally has its large ensembles stage an opera. There may be others, on special occasions; this web page is not a current schedule. Don't forget that Santa Cruz County has its own sypmphony, several chorales, and other music events.
There are several ways to get from Santa Cruz to San Francisco (or vice-versa) by public transportation: (1) Greyhound bus, (2) Combination of Caltrain and public bus, and (3) Combination of BART, Caltrain, and public bus.
(1) Greyhound. You can take Greyhound Bus between downtown Santa Cruz and downtown San Francisco. There are two advantages. First, you do not have to switch from one mode of transportation to another. Second, there is an on-board toilet (the ride is long). The cost is slightly less than other methods, and the total time is about the same or less, depending on other factors. It is best to get your tickets in advance, since students traveling to or from UC Santa Cruz may fill the bus at certain times. You cannot take a bicycle unless it is disassembled, packed, and treated as luggage. Most routes stop at San Jose, Hayward, and Oakland in between.
(2) Caltrain and Highway 17 public bus. From Santa Cruz, take the Metro/Amtrak Highway 17 bus to San Jose Diridon train station, then take Caltrain to San Francisco.
(3) BART, Caltrain, and Highway 17 public bus. As above, take the Highway 17 bus from Santa Cruz to San Jose Diridon, then take Caltrain to the Millbrae station. At Millbrae, transfer to BART and take it to San Francisco.
Note to Caltrain riders. If you are going from San Francisco to Santa Cruz, particularly on weekends, be aware that some trains are scheduled to arrive at San Jose Diridon shortly before the bus leaves; but the train will probably be late, and the bus will have left.
It is also possible to take the Highway 17 bus from Santa Cruz to San Jose Diridon, then take the VTA route 180 bus to Fremont BART station, then BART to San Francisco. This method is not recommended, unless your actual destination is some east bay location served by BART. If you are affiliated with UCSC, there is an occasional university van between campus and Fremont BART; however, it is not open to the public.
Local transportation in Santa Cruz. If you are traveling to Santa Cruz by any of the above methods, you will arrive at the Metro local bus terminal, which serves Santa Cruz (including the university) and other parts of the county. The bus arrives in the downtown area, in the block bounded by Pacific Avenue, Laurel Street, Front Street, and Cathcart Street. Actually, the Greyhound station is immediately adjacent to the Metro station, not part of it. Currently, Metro charges $1.50 for a single ride (no transfers), or $4.50 for a day pass. If your ultimate destination is Watsonville, you can get there by Metro bus; however, if you are arriving via Greyhound, I believe that most routes continue to Watsonville.
Metro buses to the university are frequent. If your goal is a day at the beach, then you might try bus 7, 19, or 20, or walk. It's about half a mile from Metro to the main beach, wharf, or Beach Bordwalk.
If your destination is the Santa Cruz youth hostel (Carmelita Cottages), it is located on a hill overlooking the Beach Boardwalk and Municipal Wharf area. You can walk there, or shorten the distance using the 7, 19, or 20 bus. For most people, the ride isn't really long enough to justify spending the money. How to walk to the hostel: From the Metro bus station, go towards the ocean on either Front Street or Pacific Avenue (the two streets that border the station). Note that "towards the ocean" is actually south here, although many people think of it as west. After a couple of blocks, Front Street and Pacific Avenue merge. At that point there is a walkway going up the hill. If the walkway is open, take it; if it is closed, then go up the nearby road. At the top of the hill, turn left, then go a block or two. The hostel is on Main Street.
Local transportation in San Francisco. Of course, this depends on where you arrive, and where you want to go. Be sure to check Muni buses routes. Muni currently charges $1.50 for a ride, with transfers allowed within a 90-minute period. Unless you intend to tour the city, don't bother with a more expensive pass. However, be sure to take a transfer even if you don't intend to transfer, since it's proof that you paid the fare.
Greyhound arrives at the Transbay Terminal, which is well served by Muni. If your goal is Union Square shopping, then you might as well just walk there. To get to the Civic Center venues (War Memorial Opera House, Davies Symphony Hall, Herbst Theater), take bus 5 and get off at Van Ness Avenue (immediately past City Hall). If your goal is a place in Marin County, then look at the Golden Gate Transit system, and sure that the bus stop serves your intended route, since Golden Gate Transit does not serve all Muni stops.
Caltrain arrives at the Caltrain station, which is relatively far from anything else. From there, you can take a variety of Muni buses. For example, number 47 goes past the Civic Center to Fisherman's Wharf. When you exit the Caltrain station, look for the Walgreens store at the opposite corner; the 47 bus boards there. This bus seems to be very crowded, all the time. If you don't like crowds you might check the Muni schedules and try a combination of other bus routes. Most of the other bus routes board on the corner diagonally opposite Walgreens.
BART serves several stations. If you get off at the Civic Center station, there are several exits to street level. If you are careful and take the exit labeled "Civic Center," then when you emerge you will be looking westward along Grove Street.
When I go to San Francisco for an evening's entertainment, I often stay at the City Center Youth Hostel. From the Transbay Terminal, I get there by Muni route 38. From the Caltrain Station, I would use route 47. From BART, I would get off at Civic Center. There are still a few blocks to walk in any case, depending on which way one gets to the city, and how much one likes to walk. There are several other Northern California HI youth hostels in the city, at good locations, and you can make an advance reservation online. The Downtown hostel is at Union Square, and the Fisherman's Wharf hostel is actually at Fort Mason, and is served by bus 47 (and others) that can take you to the Civic Center or elsewhere.
And now, the Opera. I like to attend the San Francisco Opera or the San Francisco Symphony. Here's how I might do it, from Santa Cruz and return:
For an evening performance, I would take the 12:30PM Greyhound Bus from Santa Cruz to San Francisco, arriving shortly after 3:00PM. Then, I'd take Muni bus 38 to Larkin and Geary, and walk about 3 blocks to the city center hostel, where I had a reservation. I'd check in, leave my non-valuable items on the bunk, then go out for dinner. Incidentally, the War memorial Opera Building is in the same general area as Davies Symphony Hall, the Herbst Theatre, and City Hall.
The hostel is in the "Little Vietnam" part of town, and there are numerous places to eat in the immediate vicinity, both Vietnamese and otherwise. Or, if you walk over to Van Ness Avenue, you will find a variety of eateries from Chevy's to McDonald's. The Opera has its own buffet (and also a menu) in the basement. It looks pretty good, but it is not cheap and seems to be patronized mostly by what I would call the hard-core opera lovers. The layout is rather quiet and the diners seem to treasure privacy, rather than cross-table conversations.
I typically eat at Max's Opera Cafe, on Van Ness. It has the kind of food I like, and a full bar. Max's can get very crowded before performances, but fortunately the layout can accomodate single diners as well as groups, or you can eat at the bar. Max's is often a lively place.
I have a cheap seat for the opera. Otherwise, why take the bus and stay at the hostel? The opera cheap seats are very high up, and it gets warm up there, even if it is cool and foggy outside. So, if you are going to the opera, be prepared for inside/outside climate difference. Although formal attire is not necessary, I dress inconspicuously, which is always how I dress when not riding a bicycle. Cologne is out of the question!
Walking back to the hostel, after the show, leads past some of the street life. Not much different from downtown Santa Cruz.
If I stay overnight in San Francisco and am not in a hurry to get back to Santa Cruz, I can take a bus to Golden Gate Park or elsewhere. The hostel allows a bag to be stored throughout the afternoon, even though I've checked out. It is possible to store a bike at the hostel while attending the opera, then ride it the following day. However, I'd have to get there by a method other than Greyhound. Cycling is not good in the city center area, but it's possible to put a bike on a Muni bus, and take it to a good cycling area (such as the Presidio). Or, stay at the Fisherman's Wharf hostel, which is very well located for bikes, then take the 47 or 49 bus to the performance.
What if you want to catch the opera, or the symphony, and come back the same day? It can be done. The opera sometimes has Sunday matinees. The symphony sometimes has mid-week matinees, which are very easy to get to, since the transporation is on commuter schedules. Either way, you will probably be better off using the Highway 17 bus to Caltrain, then to the end of the line in San Francisco, then Muni bus 47 directly to the performance.
You can get to and from the airports via public transporation. From San Jose (SJC), take the free VTA bus #10 to Santa Clara Caltrain station. Be sure to get the correct one, since the #10 also goes in the opposite direction. If in doubt, tell the driver that you are going to Santa Clara. There, you take the train southbound one stop to San Jose Diridon (the train is not free). The train you need will be on the tracks closest to the bus stop. At Diridon, you take the Highway 17 bus to Santa Cruz (be sure it is going to Santa Cruz, not continuing to downtown San Jose). When you get off the train, you must use a walkway underneath the tracks. As you climb the ramp to the station, the stop for the Highway 17 bus is straight out the door in front of you, not through the reception area.
From San Francisco (SFO), find the overhead passage to the trains and BART. Take BART to Millbrae. The ride is currently $1.50 and you must switch BART trains at San Bruno. (Note: In the past, BART directly connected SFO to Millbrae, but not any more.) At Millbrae, take Caltrain south to San Jose Diridon. At San Jose, take the Highway 17 bus to Santa Cruz.
If you are arriving at SFO late in the day, you may not have enough time to get public transporation all the way to Santa Cruz. If you don't mind a hostel bunk, consider taking BART from the airport to the San Francisco Powell Station. The downtown hostel is two blocks away. The next morning, you can then take BART to Millbrae, then Caltrain to San Jose Diridon and the Highway 17 bus. If using the hostel, be sure to reserve in advance.
I haven't used Oakland airport, but it has a BART train station. So you might try BART all the way around to Millbrae, then follow the above instructions Be sure to select the correct train; you might need to transfer.
Monterey County also has an airport, served by Monterey Salinas Transit, its county bus system. You can take buses to Salinas, then to Watsonville. From there, you would change to the Santa Cruz County Metro system. Several lines go to Santa Cruz. If an express bus is available, use it.