I would book CSR as soon as you are sure of your dates and then wait for a code. That way, if a code never comes, at least you'll have a reservation. This year, the Spring resort codes started 4/18. I don't think there were any before that in April because of Spring Break.
I stayed at CSR in May with my DD4. We loved it. The pool is really great and so is the playground. The resort is just beautiful in general. The bus service was also great. Some people complain of the resorts size, but I didn't find it too big at all. It never took me more than a few minutes to get to the pool, food court, or bus stop.
