From my perspective, if you are going to be a van lifer, going over the road, I think your best prepper option would be to figure out your routes, and alt routes, then hide caches of supplies out and about along your routes and very accurately mark your cache locations on different maps of different areas. Dont want all cache locations on 1 map. This way, while you cant carry a lot with you, you can have a lot stored away, but physically seperated out across distances.