Re: Riding in a 5 th wheel
Varies from state to state, and most who (used to) allow it require a 2 way intercom between the trailer and the truck.
But in any case, it is a Bad Idea. Not safe at all (trailers don't have crash protection) and not pleasant (without shocks, anyone sitting in there will become airborne at every bump). It is possible that laying in the bed over the hitch might be bearable, due to the better suspension of the truck rear axel.