With that big 5er, you're definitely going to be over the ratings of your truck. But let me give you a more "real world" example. I just bought a Wildcat (28RKBS), with a "supposed" dry weight of 8600 pounds. With my old F-250 (a 2003 with a 5.4L and 4.30 gears), I had a few hundred pounds to work with. Well, when I brought the 5er home, it really towed admirably, but wow...pulling that much trailer was an interesting experience. The wieght on the back of the truck was no big deal...it sat great. And getting up and going was not really a problem either, nor was stopping. But the problem came in making that 5.4L pull that trailer with all the wind resistance. As I said, it did an admirable job, but it was just not enough. I also went in knowing I would be getting a better truck, but I also knew it would happen sooner rather than later. After I got the trailer home, the hunt began. I now have a diesel that is made to tow. I feel more comfortable towing it, the truck doesn't even grunt, and I know it's the right tool for the job. Believe me, even if you managed to keep the weight down enough to stay within the limits of your truck, you will not like how it performs once you hit the open road. And if you live anywhere near any hills or mountains, or are planning on going that way...forget about it. Get the new truck first, then get the trailer. It's the right thing to do.
Oh, and I almost hesitate to add this, but it at least answers your question. The Cougar is a very nice camper. A friend has one and has been very pleased with it. Me and my wife really love our Wildcat also. They are both a great rig.