There's a picture of a cart on the top of this page that looks really simple to fabricate and ideal for the propels. I'm not sure if this is a diy cart... if anyone knows please chime in...
It looks like it has balance bike wheels on it which are tubeless and weigh only 1lb each. My fold up cart has 2lb tires and the cart does not fit the hull properly. I know there's been some mods to these foldable carts, but I'ld rather sell it and start over.
I'm thinking a foldable aluminum bar with two bunks/pads attached to support the hull will work. Attach some axles on the ends of the bar and that would work for the wheels. Then attach one strap on the bar to hold down the kayak from moving.
it can even be designed to screw into the back rails for on the water storage with some quick release pins for the wheels as well.