I am going to WDW 9/16-9/23 and staying offsite with my DH our 2 kids (9, 4) and my niece and her son (3). I would like to do as much as possible, can't you tell who's the disney maniac of the bunch

but I know the weather will be very hot especially for the little ones. We have plans to visit the parks 4 days and I was wondering if it would be a good idea to hop or not. What would you do? These are my tenative plans if we decide to hop.
Sun: AK/EP
Mon: EP/MK
Tue: MK/AK
Wed: MGM
I was thinking that if we hit the parks at opening then we can get alot accomplished in a few hours then head back to the resort for swim/nap then back to parks in the evening. I tried to plan the days around the EMH days, is there anyhing else I should consider? With the heat and possible crowds I don't want everyone to get burned out. Suggestions anyone?