We made our trip down this weekend. We stayed at the Fairfield in marathon, there's a Hampton right next door if you're a Hilton fam. They're both on a small marina, the Fairfield Inn has a restaurant, Sparky's, that is OK. There's a launch here, and a couple of spots for trucks with trailers (actually a yamaha here right now, lol).
We didn't bring our boat but there's tons of launches here. That said, it's easy to forget how freaking big the keys are. And how slow and heavily policed the speed limits are. Staying in the middle is nice in theory, but it ends up being 1.5 hours to wherever.
Other thoughts... If you're bringing the boat, don't even bother thinking about key west. It's a crowded hell scape of drunks on bikes, drunks on mopeds, and tiny streets with street parking, not at all suited for something that can tow a boat.
Bahia Honda is really beautiful, but somehow I thought it would be bigger. Probably because of how long I've wanted to go. Definitely recommend going.
One of the beaches at Bahia Honda was closed due to high levels of bacteria. The other side of the island wasn't closed. Not sure how I'd take that having my family swim in it, but something to note.
The water seems to get prettier around lunchtime. That's when it turns the nice bright aqua colors.
We ended up cutting our trip short because our hotel isn't as dog friendly as they claimed. They were cleaning the ros next to ours and called us 8!!! times because the dogs were barking. We got there and they're banging and clanging around cleaning the rooms, so yeah, they're gonna bark. Between the dogs and the baby, we decided we might have bit off more than we could chew and decided to head out a day early and make our final day a bit more low key (heh, get it? Cuz it's the keys. It's a joke, it's funny). Definitely want to come back with the boat and no dogs, and maybe no baby, lol. The snorkeling and stuff here seems awesome.