Your trip sounds fantastic!  That would be my kind of adventure.   I kind of took a trip like that with two friends during spring break one year.  We planned it one week before break.  Granted we didn't camp, but we drove from Chicago to Utah.  We had a blast.  You could have sworn we were drunk the whole time.  None of us ever went on a trip like that before, and so spur of the moment.  People at work didn't believe it and we left right after school ended, from the parking lot.  We stopped where we wanted and went different ways than following the map the whole way.  I can't say enough about a friends trip!