Hi. I'm new here. I realize the answers to towing are complex but does anyone here have any experience with a GMC Sierra 2500 HD, short bed in towing a Montana 3400 fifth wheeler? I'm finalizing plans and I'd like to get that combination. The salesman seems to think I should go 2 wheel drive instead of 4 because it offers more towing capacity. Also, the salesman thinks I should go long bed over short. If I go short will a sliding hitch be the answer?