I don't see this anywhere, and I live near two colleges. This is fairly rough living.
You have access to university gyms, with locker rooms and showers, and the restrooms in their buildings when they're open, if you're able to park nearby, but where are you going to pee in the middle of the night, or go when you're sick to your stomach and the buildings are locked up?
Is the money you save on rent going toward buying prepared food, since you can't cook or keep food chilled very easily? Propane isn't cheap and it's not always readily available when you need it.
Where I live, you're going to literally freeze to death, even when the winter is not extreme like it is today. In other places, you'll be so warm in there that you can't stand it. You can run the engine to control climate, but that costs a lot more than climate control in a studio apartment, which is so much bigger.
Where are you keeping your out-of-season clothes, your books, your dirty laundry, your spare bedding, your day to day wardrobe?
Can you study in there? Write your papers or homework and print it out? How about have a friend over? Bring home a woman?
In most places, it's not legal to live in your vehicle except in campgrounds--nowhere near schools, and not free. Even if you move your vehicle among multiple places, expect tickets, and hassles from cops and locals. You can also expect robbery/burglary once someone realizes your worldly goods are in there.
A dorm or studio apartment is going to be safer, more convenient, and possibly similar in cost overall.