I'm interested in this subject too. We are going to WDW from the UK for the third time this summer. We have three children. Our two sons (aged 16 and 13) both have Chronic Fatigue Syndrome (sometimes also known as 'M.E.') which will limit what they - and we - are able to do.
We planned the vacation when our older son looked like he was beginning to improve - which he has continued to do, but we can't see him being anything like 100% by the summer. What we didn't know then was that the younger son would also develop the condition. It looks like he is going to be quite low for the forseeable future.
We've had real cold feet about having booked Disney with the boys the way they are - but decided it would do nobody any good to cancel. They have a particular problem with early mornings, which won't help with efficient touring of the parks, so we shall have to be selective about what we think we can do in a day and realistic about pacing ourselves. Fortunately, we have 11 days at AKL, so should get to do most of the things we want to do over the course of our stay.
We're also travelling with my parents - my father will be 76 on the day we return to the UK. They'll be fine with early mornings, but neither of them will want to run around the whole time!
Having used Bob Sehlinger's 'Unoffical Guide' on our previous trip (1998), we were expecting to approach the enterprise in a similar manner this time - we shall still need to plan our trip with military precision, in order to be as efficient in our touring as possible, but we will need to look at what our priorities really are.
I look forward to reading any words of wisdom on this thread.