That would be my concern. It's only a matter of time before battery recharge trucks roam the streets and rescue people from offroad power failures. Cheaper than loading an EV on the back of a diesel flatbed to be taken to a recharge station, which I often see in California.
In general I expect serious off roaders will carry a generator - they often do anyway for their campsite. Of course we are talking altitude which changes things.
No, it just charges slower. You do of course need a charger that doesn't draw as much power. Enough gas to run a camping generator overnight will get you half a charge and that should get you back to civilization. If this is your normal use case a conventional engine is by far better - but for the average camper this is done so rarely lugging around a generator only when needed makes sense.