I think the Tesla power wall goes for about $5K. You could obvious make it work, and there are mini splits that are made for solar power, but I doubt you would ever save any money on your utility bill. If you want to do it just to be off the grid, that’s another story.
The thought is off-grid without having to run into town every week or two for propane. Propane would remain for tankless hot water and stove, but I’d be cooking outside as much as possible. Looks like a big coach but cooking kicks off a lot of odors, heat and humidity. It’s a pretty small space all considered, 26’ long by 8’ wide, regardless of external appearance.
I’ve admired those, but short of hanging it on the back of the RV I don’t see where it could go, and that would be a thief magnet, unlike the external component of the heat pump which honestly looks like a narrow cooler with a vented fan on the side