I use Google Maps to work out the route.
Enter the Starting point and the final destination.
Then insert all the in between destinations that have interesting sights to see or events going on that We hope to take a look at.
Sometimes it is obvious that some places to see, are clustered around or near each other ,so We choose one location as a break point. Set up Camp and do some touring.
When the distances between stops are greater than three or Four Hundred Miles apart We usually plan to overnight somewhere within that range. I try not to travel for more than six hours in any given Day.
A set of AAA Maps used to be all that We had a few Years back. Now with Google Maps and our trusty GPS it is very easy to plan a route that doesn't involve a lot of backtracking. Saves Time and Fuel.
We try to use RV Parks as Hubs for Our multiple activities , but will overnight at Walmart* or a Casino if necessary !