I pull ATVs during the winter months and Jet Skiis during the summer months, but where I go, I can either leave them anchored overnight (small cove, 3 skiis cabled/locked together) or I use a tote to pull them out individually. I would leave the boat anchored in the water (when I had a boat), but of course that may not be an option where you go.
However, I often have friends that come down with a TT; so they unhook and we use their tow vehicle if needed for launching :).
I would never own a TT or a 5er for just that reason; no way to take my toys down without double towing or driving a second vehicle.