Dude, if the wife gives the green light, that's half your battle right there.
Why do you think you lost motivation, tired of dealing with the boat or it's not the boat you want to deal with?
I'd say take Kenny up on his offer. Having some boating friends helping out might be the ticket.
Unless he comes over, drinks all your beer, and passes out in your front yard before he even turns a wrench

.
As for the hoist on the grass, could you put a piece of 1" plywood down and roll the hoist on that?
I don't know how well the hoist will move, but I would think it would be easier than the grass.
Good luck.