I use a heavy 3/8 inch links chain, about 10 feet long so that I can move the gen off the carrier and a little way away from the RV when running. I use a couple of those circular locks to lock it to the RV. The gen set has a steel frame tho I understand some do not. It is an inverter 3500/4000 Champion. I also carry a 5 gal gas can back there and run the chain thru the can handle. I have to loop the chain around a couple of times thru the carrier because it is long. This worked for 9000 miles this summer.
As for cover Champion sells a waterproof cover for $15 on Amazon that worked OK. It has a draw string around the bottom and it stayed on all summer.
If you run the gen on the carrier the noise and vibration inside will not be very tolerable. I did it once for 5 minutes or so.
