I think you are on the right track looking at something like the Sightseer or something similar with a small tow car if you want to part time travel and see the country. This combination will give your lower fuel cost over a fifth wheel. You will find the small tow car is nice to explore the surrounding areas and visiting city's and tourist attractions along the way. The shorter MH will allow you to visit and get into more NP's and SP's. There are more sites available for that size vs a 40 ft rig. Look for one with at lease 70 gals of FW. If you plan on staying a week lets say inside Yellowstone NP. Good Luck on your search.