How to properly plan x-country trip with 43' 5er?

I plan on 8 to 11hr days to get to a region(my fav is the Northwest in July) and spend 3-4 days to explore before driving a day or less to the next 3-4 day location. I found out on my first across country trip that moving too often is tiring and stressful. I got home and needed a vacation from my vacation.
As far as reservations, I like to play it loose. When moving to a new location, Mon - Wed is a pretty good bet to get a campsite. Maybe can't do that in California though with the higher crowds.