I have taken a quad two different ways. First time was loaded on a Ford Ranger I used to tow behind the coach. It was perfect to go out in hunting trips, Quartzite etc etc.
I also have a utility trailer which I made out of a single jet ski trailer. It also worked real good.
Now you do not mention what kind of coach you have, but a quad 350 CC and bigger are pretty heavy and I would be very careful as to how much over hang weight you put on that rear axle. Now if you have a tag, then there is no problem, but other then that, I would really check to see if it is not going to create a problem with the handling of the steering, plus you do not want to over load the max capacity of the rear axle.