Thanks everyone, I think things are a little clearer now. My only problem with most 3500s is how high off the ground they are. I have very little meniscus left in my knees and even with running boards, I still need a step to get in them. We will have to check them out again and see if there are ways to make them lower.
I have one more probably crazy question. Would packing your 5th wheel more heavily behind the wheels lessen your hitch weight? I realize if you overdid this it might effect he rear wheels of your truck, but maybe to a smaller degree it might help with total payload on the truck? Have I completely lost my mind?