So if living/sleeping out of a van on your grandmother's property is an option, you might consider just buying a van that is already meant to be used for casual camping. One of my best friends when I started working as an EE in Silicon Valley was an avid rock climber who basically drove to Yosemite from Silicon Valley every weekend to climb. He had one of these Volkswagen Vanagon vans (I think a Westfalia):
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Have you looked at purchasing a used camping van like these?
BTW, when I was in undergrad at UC Davis in Norcal I lived on-campus in the dorms the first 2 years, but for the last 2 years, I lived in off-campus apartments with roommates. So for those last 2 years, I commuted via bicycle to campus at similar distances to what you are planning. It was fine in good weather (but be sure to use lights when riding in the dawn/dusk/dark), but required pretty extensive rain gear during the rainy months. I don't know if you have snow at Clemson, but that would add another dimension.
EDIT/ADD -- Even if your grandmother situation is a bit dicey, does she have any utility hookups that you can share? Mostly I'm wondering if she has cable service and a cable modem. If she does, you might be able to connect to her WiFi if your van is not parked too far away.