I actually looked on a Dakota site and discovered the towing capacity is in the VIN. Mine is factory rated at 5001-6000 pounds. Knowing that I can at least determine a "theoretical" sized trailer. I'm thinking something in the 2-2500# area would be relatively doable and still allow for the extra weights of water, waste, and "stuff".. Upgrading the mechanical systems of the truck is another issue that I am very aware I need to address, along with the proper tow hitch and mounting.
And thanks for the rvshare.com site. I've already found it a viable search location.
I have the winter for planning and prep!