Capulin Mountain National Monument-- NM

It depends on how interested you are on things that are slightly offbeat. Capulin NM is only a few minutes off US 64/87, and you don't need to spend hours there; a few minutes will do. If you can't climb to the top of Mt. Rainier or Mt. Hood, you will at least have acquired bragging rights to say that you have been to the top of a volcano!

I stopped by Capulin a couple years ago, and discovered that trailers are not permitted on the drive to the peak. I didn't feel like unhooking my 16' TT in the lot at the (rather modest) visitor center and re-hooking afterward just to see the view from the top, so I left. My advice is to skip it. High views are plentiful in NM and CO.

All it is (Capulin) is a drive around and around a big volcano until you get to the top. It's a good place to stretch your legs. I don't recall how far off the interstate it is but once you get there it's maybe 90 minutes if you take in the super view.

Great Sand Dunes is well worth a stop but really needs a half day. You will want to walk out into the dunes, everyone does. Ah never mind you are camping there. I've been there but never camped onsite but I bet the sunset and especially the sunrise are spectacular photo ops.

There is a 4WD road going north, it's very sandy.