I lived there full time for 10 years, and prior to that part time for more than 10 years.
I was 64 years old when i moved there, which is actually to old to be moving to a remote area with marginal medical facilities.
I did however enjoy very much the time i spent there, especially the fishing.
I was a licensed captan before moving there and for about 5 years ran charters with my boat for the Hawks Cay resort on Duck Key where i also lived.
April would be a very good time to visit the Keys, as the tourists have mostly left and the fishing is good, actually very good.
I would strongly reccomend the Marathon area as a home base for your visit, as it offers everything you could need without the hustle bustle of Key West.
If your interested in a fishing charter for reef or back country check and see if The fishing buddy, Buddy Lapointe is still doing it . Take it from an old captain, that there are none better in the keys.