[Richard]

In my view of the world, it’s a pretty straightforward deal for an experienced guy like you. There are a few key points learned by others.

Don’t need to splain LiPoFe to you. Or enough inverter to run your stuff. Almost all Newells come with enough bay space to pack six 8D batteries in there.

Basement air is a must to have enough roof space and not have the aircraft carrier look. But you will immediately take the basement air out. You will then have two options. Use the existing ductwork with the MUST option of using a high static high flow indoor air handler to push enough air through the existing ductwork. OR the coach may lend itself to the more efficient indoor wall cassettes. The individual coach will dictate this. Jack Houpe’s coach is one that it worked in. Cassettes would not have worked at all in the coach I owned.

And if you really want OFF grid plumb the existing AquaHot heating and HW loops into a mini heat pump.