Thanks for chiming in.
Looking at it like that, it's still something that I want to do. Taking the prevailing winds into consideration - if you were going to make the trip, how do you think it would be leaving from Marco Island instead of Key West? Granted it's a longer distance, but it seems that one would be on a reach the whole way there and back. Maybe not as pleasant/relaxing as drifting along downwind - more like sailing, that is (hehe) but it seems to me that one could come far closer to a predictable (if not fixed) schedule doing the trip that way. Any thoughts?
Its about 105 miles and while it might be a reach going to the Dry Tortugas it is likely to be a beat coming back and unless the wind is south of east you may not even be able to lay the course. Motorsailing is not really an option on a typical trailor sailor with outboard.
If you can pick your weather window and have a secure forecast on SE winds for your return I think that the Marco Island return route is favourite. Both routes require a night sail on your sort of boat.
Which ever route you take be awre that the crab pot density is almost unbelievable in some spots. Make sure you have a means of freeing yourself if you get caught. It is less likely on a boat with the prop out of the water but s**t happens.