Hi Susan,
Late August is a fabulous time to visit Walt Disney World! While it is still hot, the crowds have dwindled because most of the United States is back in school.
Mondays tend to be busiest in Magic Kingdom because many guests still vacation Sunday-Saturday and they want their first full day to be in Magic Kingdom. The only other day to avoid a park is Disney's Hollywood Studios on days it hosts
extra magic hours. This park is small and it is very crowded during these periods.
When building your schedule, think about going to Epcot first as it is the biggest park and you will want good walking legs. Then add Disney's Hollywood Studios with the shows to sit and take a rest. You can then alternate Magic Kingdom and Disney's Animal Kingdom.
You may also want to take a break and go to a
water park or stay at your pool.
My best advice is to not try and see it all. Select a few must do experiences and then the rest is a gift.
Wishing you a magical vacation!
Beth