Yes, we towed our 5th wheel over that route on the way home from the UP of Michigan in the fall of 2015. It is a good, paved, two-lane US highway that goes through quite a few small towns, but no big cities, does not have much truck traffic, and crosses lots of rolling hills in western Kansas. It is farming country all the way from St. Jo to the foothills of the Rockies. If you want something different than 75 MPH Interstate highway, it is a good choice.
We got RV parks for nights in Hannibal and St. Jo, MO and in Norton, KS. We originally planned to stay at Prairie Dog SP outside Norton, but ended up staying in town due to the late hour and cost. The private "RV park" we stayed in was a vacant lot with FHUs across the main street/highway from the high school football stadium. So we watched a JV football game from our sofa after a big dinner at the restaurant across the side street from our site.
We were back home the night after Norton, so did not need to stay at any Colorado State Parks. But we have a Colorado State Parks Pass and have stayed at many of them on the Eastern Slope--Jackson Lake, Golden Gate Canyon, Chatfield, Cheyenne Mountain, Pueblo Lake, Lathrop, Trinidad Lake, John Martin Lake, etc. They all have at least one campground with hookups, most have lakes and are therefore very popular in summer, many are tree-shaded, and most have great mountain views.
Just a suggestion, but alternatives to the very popular Boyd Lake SP abound and are also very good. These include include St. Vrain State Park, two Larimer County campgrounds with hookups--Carter Lake near Loveland and Horsetooth Reservoir near Ft. Collins, and USFS campgrounds (no hookups) along US 34, US 36, and CO 72 (part of the Peak-to-Peak Highway) in the mountains.
And, just FYI, Rocky Mountain is a very large national park, not a state park. Trail Ridge Road, with its 12,000-ft, elevation, sometimes doesn't make its scheduled Memorial Day opening. But, with the lack of snow this spring, it very likely will this year. HAve a great trip!
