Two years ago, we took US 36 from Hannibal, MO to I-70 in Colorado on our way home from a Great Lakes RV trip. As others have said, it's a good 4-lane road in MO, a somewhat hilly 2-lane road across KS, and a relatively flat 2-lane road in NE CO. Little truck traffic in MO and little any kind of traffic in KS and NE CO. We had planned to stay at Prairie Dog SP in KS, but it was late when we got to Norton, we were hungry, and the SP is a few miles west of town. So we made the decision to stay in Norton on a grass lot with FHU, pull-thru RV sites ($20/night) across US 283 from the football stadium.
We picked the "RV park" (neighbor: "just walk up to the house on the hill to pay") because the librarian said that it was across a side street from "the best restaurant in town and be sure to have their mashed potatoes!" After dinner, we sat on the sofa and watched a JV football game between Norton HS and Colby HS out our picture window. Hard to beat a FHU site, a good meal, and unusual entertainment for $20 plus the cost of dinner!
However, if you are planning to play tourist on the way from PA to CO, US 50 has more interesting towns, state parks, and attractions through KS and CO. This route approximates the Santa Fe Trail, so has sites like Fort Larned, Dodge City-Fort Dodge, and Bent's Fort that are worth stopping for an hour or two each. Helps break up the trip and see places you may have only read about in history books. And, if you use I-70 only to Kansas City, I-35 from KC to Emporia, and US 50 from Emporia, you stay off the expensive-for-an-RV Kansas toll roads.
When planning your route through the Colorado mountains, take a look at my new blog
HERE.