Get a cheapy trailer from Harbor Freight to tow the kayak and leave the lights on.
Where does the wiring come out of the light bar? And where does it go? More pics would help, too.
I would cut the wires about an inch from the bar and install plugs like these or these. You could then do what I suggested in the "if they have plugs" part of my previous post. There's even a video on installing the latter ones here. I think the first ones would be easier to install if you can do some light soldering and heat shrink tubing but the others might be better if you don't do soldering.