If I could stuff the back end of SB Cruiser with batteries, I could probably do 1000 miles in it on one charge.
(but I'd probably wanna pull a trailer with a bed and stuff in it, or put camping gear on the top of the rear rack).
Depending on how much the batteries end up weighing, I might need to upgrade the rear wheels/tires, though, or add at least basic suspension (leaf springs) to it.