If you are thinking about getting a truck canopy, get one with full barn doors on the rear. I specifically looked for my type of canopy knowing that the tailgate gets in the way loading and unloading gear and the side benefit was full access even with a trailer hitched up.
I see no problem using a longer shank with your WDH but would avoid extensions unless you upgrade the truck to a system built for weight distributed loads like Torklift's double receiver with double truss extension.
Adding a high amperage connector to your powered jack and a physical disconnect is an option. You could store the jack in the trailer or truck while towing and only use it when unhitched.