Both the male and female character would be living at dorms on campus normally. Would this mean you're back to high school protocol for intimacy? :) The author hasn't provided either of them with a car yet...
Heck no! The opportunities to 'hook up' at college campuses are legendary, although the actual occurrences are noticeably fewer. Most studious 'nerd types' still get laid a whole lot, but that doesn't keep them from trying valiantly, while many (but not all) of the women are either leery of the men or out to prove how serious they are about their studies.
Still, the idea that sex is so rampant, and hookups so readily available, tends to weigh heavily on older teens separated in different colleges (or even those with one stuck at home, watching from a distance as the other enjoys freedoms they can hardly imagine). Again, a lot of rich material to play with.
If depends on how you want to play this. If the guy is serious, trying to scrimp and save to pay his way through school, he'll also be deeply unsure about his relationship with such easy 'hookups' and plenty of available 'hot guys' around, while the girl will have trouble getting the stay-at-home guy to appreciate just what he's missing by staying at home. Further complicating things, they'll both try to convince the other of what they're missing, completely talking past one another on many instances. (This is a classic conflict in hundreds of 'college romance' movies over the ages.)
Also, they secret to cars on most campuses are that they're mostly a trap. The few with cars are continually pressed into service, ferrying the others all over the place, often stuck with remaining sober while driving their drunk friends and will often resort to making demands on those same friends in exchange for their largess, further stressing those friendships.
Those without cars actually have greater freedom. With seemingly fewer options, they have fewer responsibilities, and someone is always going where you want to go too, so it isn't terribly difficult to arrange a ride. Also, because girls are so conscious of date-rape, typically girls will travel with girls, or at least travel in 'packs' (several girls going with a few guys so they can defend each other if necessary). Of course, much of that goes out the window once the drinks start pouring and good reason goes out the window on everyone's part.
The author hasn't provided either of them with a car yet...
Not necessary if you have them in the same coed dormitory. They just have to worry about those pesky roommates.
That's where the classic 'tie on the doorknob' system works. If someone returns home to find a tie (or scarf) hanging from the doorknob, they'll know to not knock on the door, forcing them to find someone else to waste several hours as they await the opportunity to return home to crash (or study for an important test).