Regarding self-protection, I wonder if a person sleeping inside a car makes any difference to the bear?
There are some hard and fast rules for bear country, but outside of those I think everyone has a different comfort level. It would be within my comfort zone to sleep in a hardsided vehicle that has food in it.
As far as self protection, here are some options:
-bear spray
-firearm with appropriate caliber and training
-medium to large dogs (mixed bag, they provide good detection/deterrent, but can aggravate some wildlife. Know your dog)
-portable electric fence. They market and sell electric bear fences, usually intended for outfitters in grizzly country. But I don’t see why they wouldn’t work around a Kia if the need was there