I can tell you the beginning of May is a great time to go. We have been going at that time for the last four years. It is hot though, high 80's even low 90's but I love it! We have booked using the AP rate and codes found on Mousesavers. But who knows if room only codes will be offered anymore! I know the moderates were always $89 but don't know about any deluxe. The crowds are very manageable also. If a line has too long a wait just grab a fast pass. I think Florida schools get out middle to end of May, and I think that would make the parks busier.
BTW, I live in Chesterfield Twp. Not too far from you. I heard that a Mall of America is going to be built somewhere in Romeo, do you know anything about it?