If your going to try to stay vehicle specific as to your rigs make (Ford, Chevy, ect) your best bet is to find a specific make dealer on you route that handle trucks. For example, our class c is on a Ford E-450 chassis, which is nothing more than a van. But many Ford dealers don't have bays large enough to handle it. But there are Ford dealers that are also truck service dealers, and they can handle rv's, even the class a based on the F53 chassis, which I believe your is.
Just google up "Ford Truck Dealers/Repair Centers" in cities along your route.
We did a similar trip in 2017, 3 months and 13,000 miles in our class c, and twice along the way I changed the oil/filter in our rig. Carried a tarp which I laid out, and changed the oil/filter in a WalMart parking lot, on side of building. Bought the oil and Ford filter from them, a catch pan for the oil. Made sure I didn't drop one drop of oil, and recycled the used stuff right there.
Steve & Cheryl + Zoey, and Ziggy, our furry kids.
2012 Forrest River Lexington 283ts
Toad, 2013 Subaru XV Crosstrek