You will run out of payload weight capacity long before you reach the maximum allowable towing capacity. Check the inside of your driver's side door jamb. There is a sticker there that states payload capacity, "do not exceed **** lbs of cargo and passengers...".
If you want your 4 Runner to last and don't want problems, don't follow the examples of those hauling larger trailers. The 4 Runner is a cool vehicle but it just isn't made for towing. With the 4 Runner, that motorcycle, the pets, a weight distributing hitch, and minimal cargo, I'd bet that something in the 3500 lb range would be a better fit for towing. You can't carry a 380 lb weight on the back bumper of a travel trailer. At least, not without sway problems.
