Re: needing a weight distribution hitch. The dry tongue weight will likely increase significantly from the brochure. My 26' Jayfeather has a dry tongue weight of 530lbs, but when loaded for the road without water it can push 650- 750 lbs.
Your manual can tell you whether to use one, also check regulations in your area as well as areas you'll be towing through. Some areas require it if your trailer grosses more than a certain amount. It has to do with the attitude of your steer axle in hard braking and maneuvering situations.
You won't need anything insane for a 26', but don't get junk either. I love my Blue Ox, and others have their own preferred brand.
With a 2500 you have way more than enough truck, but certain items apply to all light duty trucks across the board, regardless of chassis.