I only know about relocating to Florida, per se, and would have the following observations...

Are you talking about 12 to 15 weeks in one shot, or divided up into several trips throughout the year? If you're talking about staying a few months at a time, the airfare for one yearly round trip wouldn't make nearly as much difference as if you're talking about a half dozen or more trips in a year. If the weather in the winter is what you want to get away from, you could stay where you are and just be snowbirds in SXM in the winter, perhaps. And if your number one and only priority is getting the best airfare to SXM, the best airfare is going to be from the NYC area. Florida airfares are generally much higher than many places from the Northeast and the ONLY non-stops in Florida are from south Florida, as of now. This looks like it will not change, even if more carriers do non-stops from Florida, like Southwest and Jet Blue. Apparently the powers that be have already decided the new non-stops will also be from south Florida, which already has two non stops. Anywhere other than Miami or Ft Lauderdale is going to be a connection for you, or you can do what we do, which is drive 3 1/2 hours one way for a non stop.

As far as weather in Florida is concerned, weather from October through April or May is great! The weather in the summer here s*cks. As far as property in Florida is concerned, prices here are still low, so if you can afford to go ahead and buy now, you can do very well.