So you have a 4 hour drive there, an interview that could be anywhere from 4-6 hours (if they are through) and a 4 hour trip back, 12-14 hours all told. Adding

So you have a 4 hour drive there, an interview that could be anywhere from 4-6 hours (if they are through) and a 4 hour trip back, 12-14 hours all told. Adding in time to eat and whatnot you are talking about a 12-16 hour process. After a long day a 4 hour drive home could be a little sketchy. They should probably be offering to put you up somewhere for the night. For comparison, when I interviewed at Amazon I told the recruiter I was within walking distance and she still sent me an expense form.