That's going to be quite a trip! I'm sure you know, but you'll need to go through either New Orleans or Chicago to DC (depending on which train you take), to get down to Florida. I'd like to do that someday.
Anyway, no deals. Sometimes there are savings on coach travel on long-distance trains, but I'd imagine you'd prefer a room for such a long journey. Otherwise, Amtrak prices their tickets in fare "buckets," for lack of a better word, and when the cheapest fares sell out, prices go up. It continues until it's sold out. So it's best to buy as early as possible.