11 ft Waverunner in 12 ft TH Garage

I would use a 4-wheel dolly with large inflatable wheels and a removable tow bar for your water toy. As others have posted, a winch inside the toy hauler would get it up and down the ramp safely and your truck could still launch and retrieve it off the dolly.

Strapping your Waverunner down to the town hauler while sitting on the dolly instead of trying to anchor the dolly with the toy strapped on it would prevent any movement while in transit.