From where to where?
I sometimes use I-80 from Des Moines to Chicago, Angola or Toledo if I'll be going through at the right time of day. I use I-40 west into Arizona, east into Tennessee or North Carolina, but those are different destinations than my I-80 destinations.
City and town frequency depends on where you are. 50+ miles in the desrt west and across Wyoming or New Mexico, 20-30 miles apart on the southern plains or through the corn belt, closer than 20 miles east of the Mississippi.
The RV parks I've stayed in along I-80 have been adequate. My wife preferred KOAs and Good Sam affiliates, and they've all been what we expect from a KOA, whether the park was franchised or not.
East from Utah, I-70 becomes a third option, headed ultimately for Baltimore through places like Denver, Kansas City, St Louis, Indianapolis and Columbus. You can join I-70 by following US-50 out of Reno (that is some pretty empty road) or taking I-80 to Salt Lake City and going south to connect. From the west side of the Rockies to the Midwest, I find I-70 the more interesting route, as it crosses the mountains through more scenic places.