Washington DC has a TON to do. A lot of it at no cost. We went there twice. The Smithsonian's are incredible. Took the Amtrak up to NYC one day. Long day but was fun. We went a couple of years later with another family we're friends with. Hit up some of the same stuff but also saw some things we missed the first time. We spent 5 nights each time because our hotel points rewards program gives us the 5th reward night at no points cost).
NE Tour (flew into Portland Maine and then down to Boston, Plymouth Rock...and looped around through those other NE states so we could color them in). Mount Washinton in New Hampshire - my husband had some wild hair to drive up to it after seeing it on the Weather channel. Of course, I'm the driver....scared the bejeezus out of me. It was in June. Make sure your car's brakes are in good shape. Did a tour at Cabot cheese. Acadia National Park tour.
Would require longer flights but you should be able to get something direct from up there. We did a Southwest road trip the year before Covid. Flew into Denver - omg this was tiring for me (the main driver). Drove through the Rockies to Arches Park in Moab, Utah; 4 Corners; Grand Canyon; Las Vegas for 2 nights; Hoover Dam; Joshua Tree; Flew back home from Vegas. Put over 2000 miles on the rental car that week. (was alamo and there was not an extra one-way rental fee) I really wish we would have gone over to
Disneyland instead of spending a couple days in Vegas...it was okay and the kids LOVED our room (had their own bedroom) but looking back we should have gone to Disneyland to knock that one off our to-do list. Would like to, sans kids, go back to Denver and drive up Pike's Peak and maybe hit the Stanley Hotel.
I was looking at going up to Yellowstone, Dakotas, etc this summer but I didn't want to be driving all week, even with flying in up to somewhere in the area. Believe it or not, Disney was going to be easier to plan!