We typically make reservations for a major destination like Yellowstone or the Grand Canyon. From that, we plan 200 to 250 miles a day, a stop for at least 2 nights every 2 or 3 days, and an extra few days to arrive at the destination. We typically call ahead between Noon and 3 for a nightly stop. I try to find other things to see along the route to the destination, and add extra days for that.
Depending on the length of your trip, don't forget a day here and there to just do nothing. When we first retired we found that the first day or two of a trip we would go farther, say 250 to 300 miles, then slow down.
I check campgrounds both in the Trailer Life directory and on
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2019 Grand Design Solitude 310GK
2019 GMC Denali 3500 D/A SRW