I plan on buying a new Chevy Duramax, crew cab, short bed, 4x4, either 2500 or 3500 truck. I will be towing a 10,000 lb GVWR travel trailer (bumper pull). I plan on installing a 50 gallon Transfer Flo...
3500 will be safer...bigger brakes, heavier drivetrain components.
Long bed will give you a better ride loaded or unloaded. I've always had longbeds and never ran into a situation where turning radius was a problem that couldn't be resolved.