It kinda sucks, but in a disaster, I haven't seen an EV I'd leave with unless it was on a trailer. I just wouldn't trust chargers to not be affected by large groups of people travelling or simply how much energy required for fast charging.
For bugging in, I think they'd be great. Unfortunately the amount of solar required to power these things is pretty miserable.
Eventually I think they'll come up with some good generators to charge EVs. Though maybe you could get a few hundred miles away and then slow charge for half a day, at a rest stop or something until you can get further away. But I'm talking about this in a very ignorant way. Maybe you could use a 30amp RV plug to get a bit more miles per hr during off grid charging. But if that's 30A x 110V, I'm not not sure that's really getting you far, maybe 10 miles/hr of charging? From my experience with my generator powering my camper that's about 2 ga of gas, but the time is kind of an issue.
Likely there's some generators that can somehow get ~ 30a (I think there's a 50, but don't remember) from 220V, but that starts to get into bit larger generators.