[slowmover]

A far smarter idea than the "perfect" approaches sometimes aired around here. An RV isn't easy to design or build. You are to be commended for taking a rig economical by design and restore/renovate it. That is more than enough work.

The other side of "economy" is the capacity of the vehicle to remain independent of food, water and energy inputs for the longest period possible. This will be dictated by water capacity, first, and the assumption that the climate is not extreme, second. The size of the vehicle and those capacities already inherent will suggest the best time limit.

Versus ten or twenty years ago one can now utilize solar electric packages that can work in concert with a genset to run an A/C unit, but not have to have such a large generator as even a few years ago. One can do more with less (preserve propane for example). Lithium Ion batteries on on the near horizon. In other words there are improvements to appliances, insulation, running gear, etc that will net a better vehicle.

One shouldn't, IMO, favor any one system upgrade over others but strive for an overall balance while keeping weight near the OEM figure.

With all this, water is the normal enemy. And what kills nearly every RV in time.

Looks like a 3400 lb trailer. Go to the HiLo forum for more. You'll need some important particulars to do an inspection.