Doesn't need to be a gas generator (a hard sell for an EV die-hard), what about trailer-pulled battery packs? The car would need a small tow hitch and a J-plug, chademo, CCS, or similar plug in the back. Pick up a fresh battery at a U-Haul, and drop it off in your destination town.

Or would the weight be more than a (future model) Leaf could easily be designed to pull?