You'd have to stack to get all that on the tongue of a 13 footer. IMHO, one propane
tank is plenty unless you are out in the boonies for a couple of months.
measured last year at the Oregon gathering is about 300 lbs. That's with Honda 2000 Generator
gas tank full, 20lb propane
tank full and a group 27 battery
. You'd be surprised how heavy the tray and box are.
I'm just within my total trailer weight
differential to tongue weight. Whatever that percentage is.
My trailer actually tows better now, than before I put the generator
on the tongue. That would be with or without the anti-sway bar.