My wife and I have wintered in Central Florida (near Disney) for quite a few years now. We feel the best time to visit Florida and Disney is Jan/Feb. Weather is always good in Florida. Obviously, you can get cool/wet weather anytime, but generally it is nice. There aren't as many families vacationing right after the holidays and before spring breaks start, making it a little less congested. But make no mistake, Florida is very busy during the winter months. Traffic is terrible, resorts are busy, and there are just a lot of people around.
Whoever gave you the specs for the trailer was way off base. I have a 2004 36RS3 (36'9" long), ordered new in the fall of 2003, and the specs on it are:
Dry weight - 12,500#
Dry pin weight - 2500#
GVWR - 16,000#
It is still a great trailer and we love it. To quote one of the other posters, it IS built a lot better than the new ones. We just looked at new ones at the Tampa RV show and yes, they are nice, but the quality has suffered under the new ownership.