For a cat, I got a tilt trailer meant for snowmobiles and put strips of outdoor carpet where the tubes slide (get the proper glue) and added a strip of recessed molding at the rear of each strip. Then I mounted a geared winch (about $35) at the front of the tilting bed, using the boltholes for the latch that hold the bed down.
The balance was out-of-whack (notice how far forward the wheels are), so I took it to a trailer shop and they figured out that the dealer had mounted the axle backwards, with the trailing arm facing front. Turning the axle rightways was a great help, too.
Being able to tilt the bed into the water makes loading a one-person job.