You will love going at this time of the year......... we've been the last 3 years in a row, and this will be our 4th......... we love it, very low crowds, value season, nice weather, last year we were able to swim every night, it was in the 80's during the day ..... but it can get cold too!!
As far as room codes, sometimes you can get codes, and yes they are listed on mousesavers when they come out, for discounts on your room. There have not been any codes for next year as far as I know......... but you never know, some may come out........ if you book your room, and a code comes out, you can call and have it applied to your reservation. Just keep watching here or mousesavers.
You won't be disappointed with going during this time of year, have fun!!!