If I were you I'd wait to buy a used bike once you get to Santa Cruz. You won't have any trouble finding a decent one for pretty cheap. Most people ride road bikes, but I've certainly seen plenty of hybrids.
There's a farmer's market in downtown Santa Cruz on Wednesdays and Sundays (I think-- it's either Sat or Sun, maybe both. but def Wed.) and a larger one at a community college in Aptos (a bit too far if your only mode of transportation is a bike. even taking the bus there would be a chore, but it's worth checking out if you have a friend with a car who's willing to get up early on a Saturday morning.) There's also a couple natural foods stores in and around downtown SC. I can't help you with the farm shares- I just don't know. Sorry!
If you're coming from Philadelphia, the bar scene in SC is going to be a disappointment. There aren't many to choose from, but of the ones that are there, most are dives. You'd probably like 99 Bottles, which is a small pub with, you guessed it, 99 different kinds of beer. The atmosphere is laid back, the food is okay, the service is always horrible, but with 99 kinds of beer to choose from you won't care too much.
Craigslist is definitely your best bet for finding a place to live. I have no clue about campus housing so I can't help you out with that, sorry. But avoid any place near the Boardwalk. That's Beach Flats, as I mentioned in my previous post. Beach Hill is right above that area and consists mainly of old Victorians and the rent there can be a bit cheaper. It's not quite as bad as Beach Flats, but it's still a bit sketchy. The area of SC you should be looking at is the West Side. That's where most UCSC students live. I'm not sure how many studios or 1bdrs are available in that area though. It's mostly large houses with a few students sharing. Downtown SC is another good area to check out that's within a reasonable distance to campus.
Hope that helps. Good luck!