I usually go off season; Sept, Oct/Nov and Dec.
I just went the last full week in August (NO Labor Day at all) this year for a girls-only trip.
I prepared myself for crowds and HOT HOT HOT. Well, it wasn't that bad crowd-wise especially if you go early and leave when it starts to get crowded and even more HOT!
I was pleasantly surprised. I think you should go early and leave for a heat/crowd break and then go somewhere else in the later afternoon/evening.
Don't forget ponchos for the daily storms.
Enjoy planning.