Rarely mentioned National Parks and Monuments.

We did Teddy Roosevelt south unit on this last trip. It was actually pretty scenic. Plenty of buffalo and prairie dogs. Good loop road ride only takes about 45 minutes. The only issue was that they were reconstructing the entrance road and you had to follow a pilot car through the construction.

Back in our tent camping days we did Lassen and Kings Canyon. I'm sure they're not as good now as they were back in the 70s when we did this. Too many people there now.

We did both units of TRNP this summer, yes it was scenic. But we got out of the truck and there wasn't that much to do other than the loop road. Especially in the north unit. And it is a long way away from anything, Badlands is the nearest park. We didn't go to the old ranch site since Rangers said it was a long drive and nothing to see when you get there. We stayed overnight and did the north unit on day 2.

And BTW Custer SP in the Badlands has more Bison and Prairie Dogs.

Death Valley is visited by many RVers and some tent campers in the right seasons. I was there in March (105F each day) and campgrounds were about one-half full. I saw quite a bit of the park in three full days. Found the Shorty Harris/Jim Dayton grave site interesting.

Kolob Canyon - the forgotten side of Zion.

We've been to several of these over the years. Many are of great interest to geologists and archeologists. (The popular National Parks and National Monuments are also of such interest, but that's not why casual visitors seek them out.)

Cuyahoga Valley NP is actually in Ohio - just south of Cleveland.

We've been to Theodore Roosevelt Island - not the NP, but a national memorial. :)

ReneeG wrote:
Kolob Canyon - the forgotten side of Zion.

Yeah on our list for summer, good boondocking spot on the lake too I've heard. There is also a road around the backside of Bryce with, IIRC, the Pink Cliffs. Those are smaller hoodoos with no crowds.

Some comments on a few on your list:
1) Cedar Breaks NM UT - High elevation means snow lingers late and returns early. Last time we were through there, some of the interior roads on the CG needed some work
4) Death Valley and Great Basin are rarely mentioned. Death Valley is on our to-do list once DW retires and we can travel somethime other than summer. Seem to get to GBNP every five to seven years. Some great hikes. If your rig isn't too big, camping at Wheeler CG even in the summer is quite tolerable temperature-wise. Some great hikes around Wheeler Peak.
5) Guadeloupe Mt NM-- we stopped but it seems to be a serious hiker only park. Little road access. Did little hiking there 35 years ago. Need to return.
6) Kings Canyon CA-- Over shadowed by Yosemite - Don't forget Sequoia neareby.
7) Lassen Volcanic CA--really should be more visited - Nice hike to the top and some of the thermal features give just a glipse of what Yellowstone has in spades.
8) North Cascades WA - Had to cancel last time because of the fire!
9) Saguaro AZ - Did this between Christmas and New Years. Perfect time to go.
11) Basin and Range--who's ever heard of this one? - Basin and Range has only been around since 2015 so pretty new.
12) Browns Canyon CO ditto above - Browns Canyon is kind of overwhelmed size-wise by the Arkansas Headwaters Recreation Area
14) Colorado CO--Been there a couple times not even good hiking -Nice CG (Saddlehorn) that makes a good base camp when visiting Rattlesnake Canyon arches or mountain biking the various trails around Fruita. Cooler up there at night and great views of the valley.
16) Oregon Caves OR--been there a looong time ago. Did not make any big impression - The caves have suffered a lot of desecration over the years, but the Chateau makes the whole visit worthwhile. The stream that flows out of the cave is channeled to flow through the dining room!

Great Basin has only been around since 2015 so pretty new.
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I think you have GB confused with one of the other new parks.

Wonder how many of those might lack any hook-ups? That helps keep the crowds down. But I'm sure many of those would be great and maybe less used.