Planning a cross country mega-trip (and some Canadian cities)... place suggestions? Other tips?

[Blue3]

I'm planning a 3-4 week mega trip, with the rough plan of:

Portland, Maine (not long)
Burlington, Vermont (not long = been before)
Montreal, Canada
Toronto, Canada
Buffalo, NY (not long)
Chicago (not long - been before)
Milwaukee
Minneapolis
Sioux Reservation
Badlands National Park
Yellowstone National Park
Seattle
Vancouver, Canada
maybe Portland, Oregon (not long, spent months in before)
Yosemite National Park
LA (not long)
San Diego
Vegas
Grand Canyon National Park
Navajo Reservation
Salt Lake City
Denver
St. Louis Missouri or Houston/Dallas/Austin Texas
then New Orleans after one of the above
Everglades & Miami
Savannah Georgia
then St. Louis if did Texas first, and/or Nashville or the mammoth Cave national park
Raleigh, North Carolina (have family here but never been)
maybe NYC (haven't spent a night here since a kid, skipping Philly and DC since I've been there recently)
then home, going through Albany and my sister's place on way back


Tips?
Suggestions?
Things to add or subtract?
Certain places in these locations to check-out or avoid?

I'm looking on mostly sleeping in my car, at cheap RV sites or overnight parking lots. Cheap meals (I don't eat much), laundromats. No expensive tourism, just see the sights and the free stuff, get a feeling for each area, spend more time in places I like and less time in places I don't like.

So the main cost would be gas, which seems to be about $300 a week.
(I'm thankful I can take a long birthday vacation this year, and then just do some remote work in the last week).