I have an 11' camper. I use a Torklift Superhitch and 48" Super Truss extension. I tow my 4,500 pound boat on a tandem axle trailer. I also sometimes tow my 5,000 pound 7 x 14 tandem axle cargo trailer. The set up works great.
I'm not sure what 2 ATVs and a trailer weigh but I'd guess it's a good bit less.
Actually, the hitch I'm using is rated up to 6,000 pounds trailer weight without a weight distributing hitch and 12,000 pounds trailer weight with one so I'm no where near the limits of the design.