Why not do a tesla front and rear motor of and x or s. Their are a few controllers that will do it. My dream is to do one of these with solar on the roof too. You could use whatever batteries you wanted but most economical would buy a crashed dual motor S or X and part out what you don't need. You can get a wrecked chevy spark ev for under 3k and it comes with a decent 21kwh battery. You could then just plugin at rv parks and juice up and power both propulsion and the rv off the batteries.