Take a look at the slideshow in this link. I just installed a Lewmar V700 on my 255 Freedom and used this procedure as a basic guide. If GW offered the windlass package for your boat when it was originally built, it should be pre-wired for a winch which saved me a ton of time.
It was an involved project but if you are comfortable pulling wire, turning wrenches, and cutting/grinding fiberglass, you can get it done. I actually tried my new windlass for the first time yesterday and it worked like a charm. When I get down to my boat later I will take some pics of the project. Good luck.
Here are a few pics of my recent windlass install. I also installed a new Garmin so I was pretty busy before the boat went into the water this spring. Sorry for the side-inverted photos. I do not know how to correct this issue.