I'd ask whats the purpose of driving?

is it to see places on the way? if not, I think flying might
come out to be cheaper.. with the gas prices this high.



If you do Intend to see places in-between, I'd say split the
driving time.

Do the long haul early in the morning. Say 5 to 7 hours.
See the place, go around, lunch etc.. etc.. and then
drive off for another 2-3 hours before calling it a night.

example:
5:00 AM - 10/11:00 AM - Drive
11:00 AM - 4 PM (enjoy the place, relax)
4:00 PM - 7:00 AM - Drive

(adjust the timings for rush-hour areas.)