Hothouse saidWhen I was at Big Ruby's (great place btw) it wasn't all male, but that may have changed.
I was there a few months ago and they still permit women, though few stay there. And it remains clothing optional for all, sort of like a nude beach is. Be prepared to strip in front of women, and see them naked, too, if any are in residence.
It is indeed very nice, perhaps with the most attractive grounds of all the gay guest houses in KW. JPtheBITCH mentions the "house" but in fact, like many KW places, it's comprised of several separate buildings, converted from older houses. But that only adds to the residential sense, each room different from any other, not like the universal sameness of modern chain hotels.
A strictly male clothing optional hotel, right on Duval Street, is New Orleans House. Not as refined as Big Ruby's, more in the Key West "ramshackle" tradition, it features a poolside garden bar that's popular with local gays.
So that a single guy is more likely to meet other single guys there, whereas Ruby's is for guests only, many of them couples. I love when I find myself at the bar drinking next to a totally naked guy who just got out of the pool. Or just sipping my drink and watching guys play naked water volleyball.
It's also connected to the Bourbon Street Pub, which is totally public, and can be cruisy at night when they have male strippers performing. Best rooms in my opinion are on the Grand Balcony where you can watch the Duval Street scene, and some have rear doors to the gym and nude sundeck in back.
I also like Cypress House for a mixed crowd, gay owned but guests include straights & females, not clothing optional. But great complimentary hot breakfasts and a generous happy hour. OP e-mail me for more info & details, and we know many of the owners and hotel managers to refer by name, and likewise good restaurants and other things to do. I can send personal pics of some of these places, as well as links.