Define van. Some folks take that to mean the Mystery Machine from Scooby Doo, but locally soda/beer/etc is sold out of giant trucks, semis with trailers.

I think you'd have better odds with a tradesman's van/truck for some obscure service. Not a craft meth heads would be magnetically attracted to steal and fence tools like a plumber. Something unappealing like grease trap cleaning service. Or contents you don't want to screw around with, like an exterminator service.

You'll run into some interesting state laws about commercial drivers licenses, and registration of commercial vehicles. Just because you're sleeping in it, doesn't mean according to the cops that its not a commercial delivery vehicle that you've borrowed or whatever (who cares why) and as such both you and the truck should be licensed to actually deliver sodas for hire. Some states have weird laws. You may even be required to have a business license and business insurance to get the commercial vehicle registration.

A magnetic decal sign applied to a plain old van when stopped might be wisest. Can't be pulled over for something you're not displaying and when you're parked, unless you're about to get a parking ticket, no one cares if you're a properly registered commercial vehicle anyway.