The major companies who make RV have a standards body that they in theory build to their standards. Additionally the van maker publishes an “upfitters guide” w

The major companies who make RV have a standards body that they in theory build to their standards. Additionally the van maker publishes an “upfitters guide” which explains what you can do and how to do it safely. The more professional custom van builders will take their complete rig to a truck weighing scale before using / selling. In general the camper vans are a lot safer than the big busses (class A) or regular RV (class c). The shell of the van and the front seats have to pass some safety ratings. With the class C being made mostly of plywood, they usually just blow up when they are rolled over. I did a lot of research on this before purchasing a Winnebago van. They seem to take safety a bit more seriously (ie the back seats are tied into the chassis and are from a known bus seat manufacturer).