[JacobAziza]

I'm a full-time RVer (8 years now)
7500lb (empty) 32ft trailer and 5500lb truck.
My technique for getting 25-28mpg is as follows:
I parked the RV a couple years ago, and disconnected the truck.
Best of both worlds, decent mileage, and an extremely energy/water/cost efficient home.

I used to have a 26ft class C, and switched to the trailer because this technique did not work in the class C.

I bet the thing that would make the biggest difference in the class C would be driving slower. Like 45mph. On the open highway, get a CB radio and you can warn approaching semi trucks.

Depending on where you go taking out the roof A/C doesn't seem unreasonable. Replace it with Maxx Air or Turbo Fan vent.
(BTW, no, you cannot run the A/C from solar panels or the house battery, the draw is just too much.)
If it is too hot to forgo it, try an evap cooler.
On the same note, it should be easy to take out the belt that runs the engine A/C (unless its a serpentine belt) which would remove the small drain the clutch still leaves, and remove the temptation.

I have had such success running sans alternator that I finally took it out altogether today. Since you already have deepcycles, it should be easy, just rewire a battery switch to leave the main starter as an emergency reserve.

Adding solar to an RV is very easy. I did it on my old class C.
Much cheaper than in a house, since the systems are already 12v and there is no utility inter-tie.
I got a 110watt panel, charge controller, mounting brackets, and wiring from an RV place for $500. Only used shore power for the microwave and A/C.