Are we considered "trucks" on the road?

Whether or not the truck law applies to RVs, I like to drive with the trucks on the open roads anyway. I usually find one that is either unloaded or carrying a light load and is making good time, then follow it at a safe distance, of course. When "drafting", if we get too close, we tend to be pitched side to side so I back off to the point where things settle down.
I usually get good mileage doing this as well!