One problem with minivans is the door. You can't use it to stabilize your self when getting in or out like you can with a hinged door. The other as has been mentioned is the step. It's not a height problem, but a distance one. The seat is too far inboard for a person to just turn around, sit down, and then swing their legs in. When we drive my mom around, she gets tbe front seat of whatever we are driving. The full size door with it's larger opening allows her to hold on, turn around, sit down, and lift her legs in.

I suspect anything with a full size rear door and seat close to the opening will work. No plush cloth seats either; too hard to slide in and out of. Maybe a base model 2wd crew cab pickup truck with a cap on it?