My factory installed hitch is very stout, but only rated for 300 lbs hitch wt, and 3000 lbs towing. In reality, the hitch could likely handle double that, but thinking that FW suspension/tires may be reason for low rating.
Hauling several ATVs on a trailer built to handle 3-4 is going to be much more tongue wt, than those of us double towing motorcycles. Even 2 ATVs, with one close to tongue is going to be a lot of hitch wt.
Maybe trade the ATVs for some dirt bikes, which IMO, would be more fun anyway. With the bikes, you could go either way, double tow, or smaller toy hauler.
Jerry