We did 16,000 kms from Mexico through the western U.S. and then across Canada and down through the midwest. We boondocked a lot, used Passport America and always searched for fuel using GasBuddy. I realize that fuel is cheap now but you might as well get the best prices possible. We also took advantage of FreeCampgrounds.net which was one of the best sites for boondocking and inexpensive campgrounds. Get a Flying J card and the dump station is discounted to $3.
We spread out the trip over four months so that based on the math, we would drive 250 miles in a day, stay for three and take off again. When we found a place we liked or wanted to visit family or friends, we did two days driving and stayed for a week.
It worked out great and was the best rv trip of our lives so far. South America next. Have fun and safe travels.