Sounds like you already have an idea that would work. Lock that sucker down. It's amazing how many generators will just vanish!
We are thinking of building a hauler for our future scooter. We want to do a dual "receiver hitch" on the front of the bus. We built the rear receiver so it can't be too much different (just twice the work!
My biggest complaint about my Hitchhaul is that it "wobbles" unless the load is balanced. A dual receiver would fix that.