Downtown Knoxville has several nice hotels (Hilton, Marriot, Hampton Inn Downtown, Crowne Plaza). Better reserve a room quickly though as they get booked well ahead of time for football weekends. If you stay downtown, you can walk to the Old City, Market Square, and all clubs, etc... However, at 19, you may have trouble getting in most of them...
THere's also a nice Holiday Inn downtown at the World's Fair site....
If you can get reservations at any of the above Hotels, you're within walking distance of the UT Campus and all the activities, restaurants, bars, etc... in the UT/ Downtown area (you won't have to drive anywhere)