I have been on a J34C, but don't recall the forepeak setup. However, if there is room forward of the V-berth for a chain locker, all you need to do is mount the windlass with a suitable backing plate. An above deck windlass is a lot easier to mount than one with the motor under the deck since all you have to do is drill bolt holes and a hole for the chain to pass through. In my opinion, a windlass install on your boat is an easy do it yourself project. The hardest part will be routing and pulling in the electrical cables.

Electric winches are also pretty easy to install, but they come with an additional requirement if you are talking about sheet winches. That is battery capacity. Electric winches really suck the amps. If you are going to use them to haul in the sheets, you will need to upgrade your battery bank. An electric winch for the main halyear doesn't need any extra battery capacity since you only use it once each sail. Electric winches are another easy do it yourself project.

As far as handling the main goes, you can probably go with a coastal Leisure furl furling boom.