If clothing optional is important, maybe try Haulover Beach in Miami. My husband and I are thinking of going there in April. We're going to skip SXM this coming year. A google search showed us that Haulover beach has clear, warm water (about 75 degree water) and the area has an average air temp of 82 - 85 degrees in April. There's a family section, then a straight section north of that, and also a gay section north of that. There's technically no alcohol allowed on the beach, but "technically" is the operative word, and you can always fill a couple of stainless steel water bottles with some ice pieces and rum punch !!!

There's also a clothing section south of the nude areas, marked clearly by signs and fencing.

There are hotels minutes away by car and also by public transportation/Uber, etc.