We use our truck (GMC 2500HD w/Duramax) to tow our boat (CD-25) or a 5th wheel RV. I notice that the "road manners" are more pleasant towing the 5th wheel, compared to the boat, even though the 5th wheel is significantly heavier. You are putting the weight over the rear axle instead of on the back of the frame, so that is to be expected.
The BIG downside of a 5th wheel tow is the fact that you lose the truck bed for storage. We are out for months at a time with our boat; being able to use the covered/lockable truck bed as our storage for spares and other-season clothes makes our time out more pleasant. Yes, you can buy storage pods for inside the truck bed and around the 5th wheel hitch, but you are giving up a lot of storage space.
We don't notice any sway with the boat back there, but the ride is better with the 5th wheel.
Best wishes,
Jim B.
Another Texas guy who tows to either coast from the very southern tip of Texas... we have to drive north for about 7 hours just to get to "central Texas." 😉