Florida has a waterway down the whole east coast of the state, with many great places to go. If you end up there, I will give you a list of my secret spots. You don't have to go in the ocean at all, not really recommended for a houseboat.
I would avoid the Bahamas. It is very expensive and hard to leave a boat there permanently. You can cross in a houseboat in summer on a good day, but then you may be trapped over there until the following summer. Hurricane season in the Bahamas is no picnic.
I go to the Bahamas, Andros Island, but I don't have a houseboat and I have a friend who lives there, which is a huge advantage.
The west coast of Florida is very nice in winter, with lots of good cruising. Get a cruising guide and pick some spots. I had been going to Sarasota since 1962 but it is crowded and expensive now, you would probably find better cruising further North.
I have been as far west as Biloxi, and personally prefer Florida, but the Gulf Coast offers some nice cruising.
1975 32' Flybridge Sedan, twin Perkins 6-354 diesels, 1:1.53 velvetdrives, 16 X 19 props. Merritt Island, Florida