I do the solo thing too most of the time. I've always got everything ready to go when I back down that ramp. Like others have described, I just jump out and pull the boat to the shore/side and tie it off, then park the trailer.
The only time I've screwed up is once tied off too loose. The back of the boat swung under the dock between the ramps and took up the ramp next to me. The guy there was able to launch but had to push my boat back so it wouldn't bump his. I apologised and he was very gracious and didn't voice any complaint at all.
Launching or trailering isn't a problem to me.. but getting that ole Seahorse to start takes a little time. I have to choke and choke and choke...usually a five minute ordeal. Once it starts it runs like a scalded dog. Thank goodness and my friends at crappie.com, I have a trolling motor to get me away from the ramps and out of everyone's way while I fight the horse.
It's in the shop now, getting a much needed servicing. Maybe it won't be so hard after I get it back.
"Be Ye Fishers of Men" You catch them- He will clean them