Even though you've announced a severe cutback in the magnitude of your journey I can't resist adding my comments on your original itinerary. Perhaps someone else can make use of it. I'm not familiar with New England so I'll start at Niagara Falls.
I want to ping-pong the US. I live in NC. From there to Maine and New Hampshire, down the border to New York to see Niagra falls. Couple days there, along the Great Lakes in Michigan
Definitely see Cedar Point in Sandusky, Ohio, the roller coaster capital of the world.
Through Chicago (always wanted to go through it)
Go to the top of the Sear's Tower, take a walk around Navy Pier. Plus the Biograph Theater where Dillinger saw his last movie is still in business. You can walk down the alley where he met his fate. And there's a church just north of downtown that still has bullet holes from one of Capone's drive-by shootings.
then to St. Louis (of course for the arch)
Don't forget to tour the brewery. If you like trains there's a little-publicized but magnificent train museum SW of the city.
to Kansas City, Missouri to a place called Ruby's Soul Food my dad suggested. Through Wisconsin
Harley-Davidson Museum in Milwaukee. World's largest mall just south of Minneapolis.
Theodore Roosevelt National Park
Glacier National Park has enough scenery for two lifetimes. In fact I recommend you cross the park via Going To The Sun Road then loop down and back via U.S. 2 (Theodore Roosevelt Highway) for some more scenery. While on U.S. 2 stop at the goat lick. With a long lens you can get some great shots of the wild goats. Amtrak uses the pass and if you time it right you can get some shots of the train. While in the park do some hiking. If you're in shape I recommend the hike up to Grinnell Glacier. Don't forget to buy bear spray.
and Washington and British Columbia for some nice photo ops. Come down diagonally through Utah,
The Bonneville Salt Flats, particularly if you can manage to be there during Speed Week when the hot-rodders are trying to set land speed records. On the south shore of the Great Salt Lake is Saltair where the cult movie
Carnival of Souls was filmed. It has some interesting architecture.
One negative. Don't bother seeing the Royal Gorge Bridge. It was built as as tourist trap, a bridge to nowhere.
and stuff zig-zagging to Kansas, Oklahoma then over to California
San Francisco is a city not to be missed. I've been there three times and still have not seen it all and hope to return. If you want to see Alcatraz, I recommend it, you'll need reservations in advance.
and down the coast. Come through California and go on the bottom border of the US through Nevada to Las Vegas
Just NW of Vegas is Death Valley National Park, another great fix for the scenery junky. Why visitors to Vegas will take the trouble to visit Boulder Dam and the Grand Canyon, but skip DV is beyond me.
and of course the Grand Canyon for a couple of days because I want to actually go down into the canyon.
If you want to ride the mules down into the canyon you need to make reservations, and you must not weigh more than 200 pounds. If you're going to hike down take plenty of water.
East of the Grand Canyon is Meteor Crater, Arizona. Definitely worth seeing, particularly if you're a science buff like me.
North of Flagstaff, AZ is Wupatki National Monument. If you are there at the right time of the year, we were there in June, you can experience what I believe is one of the wonders of the world. There in the middle of the ruins, with summer heat practically boiling you alive, is a hole in the ground with cold air blowing out of it. The explanation: the area is mostly volcanic rock that is very porous. During the winter air settles into the rock and gets cold. When summer arrives the sun starts to heat the rock and the air. The cold air expands and blasts out the hole. When we arrived at the ruins I decided that the place was static and left my movie camera in the car. I have a still of my wife looking into the hole with her hair blowing upward. I would love to have gotten a movie of it but I was not going to hike back to the car for the movie camera.
Through Texas and Lousiana.....possibly to Florida.....................then back up to home, North Carolina
~Michael~