As far as most surprisingly good NP and NMs, I‘d go with:
1) Big Bend
2) White Sands
3) Badlands
4) Great Sand Dunes
5) Muir Woods National Monument
I plan to visit White Sands along with Carlsbad Caverns in May, looking forward to it.
Maybe I missed it, but I do not see any mention of Crater Lake or Death Valley. I would put both on my list of pleasant surprises. Crater Lake is absolutely beautiful. I visited Death Valley several years ago in January, which was the perfect time to visit. Enjoyed it a lot more than I expected.