I recommend the Good Sam trip planner. Look at the distance you need to go. Figure the distance you can comfortably cover before you need a fuel stop. DW and I can do around 250 mi or so between breaks. That comes down to usually one break and one fuel stop. We try and plan our overnight for the second fuel stop. For example we are planning on another trip this summer to the OR coast. Total trip is 900 mi. We'll overnight about 1/2 way and take a fuel/break stop at about 1/4. We use the trip planner to see what that works out to for towns or places to stop and see the sights.
In short, 400 to 500 miles per day is about what we average with stops at 200 to 250 miles.
FR Wildwood 22 RKS
2007 1/2 Dodge 2500, Cummins 6.7
Retirement training completed
Currently enjoying second childhood