You want to tow a 12 foot trailer behind a 32 foot ultra light frame on uneven ground????? The most notorious thread around here is one of the ones Turbs posted where a guy towed an 8 foot trailer with a single golf cart behind his (he had a heavier frame than you) and his frame buckeled and cracked.
Good luck and even if you "beef" it up this is not a mod this is a complete frame rebuild and it still isn't guaranteed to work. I'd look into a toy hauler for something like this.
2015 Forest River EVO 2850
2012 Dodge Ram 2500 6.7 Cummins
Yamaha 2k x 2 with parallel cable
EMS 30 PI portable w/ Edison plug
Nights Camped (2016-13) (2015-13)