I have the same Predator 4000/3200 Generator that I bought earlier this year. I have a rack on the back of my trailer but wouldn't dream of carrying the generator on it. I think the generator weighs a lot more than 110 pounds, personally. We carry ours in the back of our Suburban which isn't optimal but is our only real choice. Fortunately, the generator is pretty leak-proof so fumes aren't really a problem. I take the back seat out and make sure the generator is riding ahead, or at least over, the rear axle.
BTW-- It's a great generator for the money. I really wanted 2 Honda's, but couldn't justify spending $2000 for something that would be be used so little (in our case).