shaselai
ACNguy
I guess I don't know your financial situation but plane tickets aren't really that expensive...that 12 hour drive is at most a 1.5 hour flight. I live in the midwest and visited Darden, Duke, Columbia in addition to all of those in the midwest...
i did check plane and its about 200$ for 3.5hr plane ride. with rental hotel prob 300$ish. I get crap for vaca days (~1 day/month) as well. Major thing is probably me trying to juggle vacation time for visits to closer schools and saving for family stuff (like thanksgiving, xmas etc.).
don't forget that for many schools, if you do get an interview invite, you'll likely have to make the trip back to campus again to interview. and while phone interviews are ok in some situations, the school might wonder why you made the trip to visit them, but not to interview, which is arguably more important to do in person.
if you could bang out all (visit the school, city, and interview) during the same trip, it would be worth it as ACNguy posted above