There is no way for anyone here to answer that question. Once everything is hooked up, inflate the bags until you are satisfied with how level it is. Then you will know. The ATV is probably not going to make much of a difference, unless it is very heavy and placed quite a ways behind the trailer axles.
curmudgeon: noun; a crusty, ill-tempered, irascible, cantankerous old person . . . .
79 27' Holiday Rambler Statesman, 78 32' HR Imperial, 85 36' HR Imperial 5th Wheel