I used to drive my 1973 Chevy Luv, to my cabin in the woods, about 175 miles from my house. So wanting 300 miles for margin and then be able to charge. There is no power at the cabin, its 5 miles from a paved road. Heck just stack crates of batteries in the bed.
What would be the expected price of an extra battery? I do need the extra margin to get to my backwoods areas. Or just mount a generator and a fuel tank, kind of easy to do on a truck, as a back up plan.