I have not read all replies, but one thing I have NOT seen is "break days".
We try to travel 300 to 350 per day. BUT, not more than two or three days back to back (to back). We try to travel two days (600 to 700 miles) max and then spend a day in place. Laundry, maintenance, groceries, the pool, or just sit around. I'll stick a third day in if there is really some place we need to get to or it we are going to spend 4 or 5 nights in one place.
It is important to note that we do not "camp". We tourist by RV. AND, we are retired.
On our main trip this Summer we spent 3 days at Gettysburg; 5 days at Boston; 4 days at Bar Harbor; 5 days at Bay of Fundy; 3 days at Quebec city; 3 days at Montreal; and then back to Florida. All with the grandson in tow. The main thing that made it possible was the rest days. One extra day between Orlando and Gettysburg, One extra between Fundy and Quebec. Two extra between Montreal and home, etc.