I went with my parents in mid-July '00 to help them with my three nieces ages 5, 8 and 10. My then 56 yr old mom had just finished chemo for breast cancer (she's still doing great), so she was bald AND she is allergic to the sun (gets hives). My then 61 yr old dad was three months out from a triple bypass. They had been looking forward to taking grandkids to WDW forever. When the cancer happened mom and dad decided to not wait any longer.
The point of this is that it was HOT/HUMID and they were not in the best shape, but we had a BLAST. After lunch we went back to the Hotel (CR). I took the kiddos swimming while mom and dad took a nap and showered. We then headed out to the parks for the evening.
To celebrate their 40th wedding anniverversary, they are taking the entire family of 15 to WDW ----- IN MID-JULY. Its when we can all go and its still soooooo fun. Just be smart: Rest in afternoon, Lots of Water, FastPasses and REMEMBER TO ENJOY NOT STRESS. Life is too short, go when it works for you and yours!