I pull my 34 foot enclosed with a 34 foot class A. I have done no modifications to the MH and hav no issues. It was already braced up at the rear because the generator is back there. My trailer loaded is right around 10,000 pounds. I am selling the trailer though, because its a Pain in the a$$ to drive a 76'4" rig around to get gas and whatnot... I always heard that you did not want a trailer longer than your Motorhome.
ALWAYS CHECK THE CHASSIS GVW....
I hope this is helpful...