If you want to stay faithful to Old 66, you may want to sidetrack a bit to find a gas pump. There are only a handful of gas stations along the original route, and between towns and cities, there is nothing else but wide, open America. Good luck finding a working pit stop in the middle of nowhere.

This becomes even more important in traversing Old 66 via RV. The best fuel savers available can run up to 12 mpg, so be prepared to refuel more often. Diesel used RVs for sale are a good investment since diesel fuel packs more punch, giving you more miles per cycle. Don't forget to look for propane refilling stations, as well.

http://www.johnsonrv.com/blog/post/2014/08/04/buying-and-prepping-a-used-rv-for-sale-for-the-journey-along-old-66.aspx