Really, my main plan was to take it slow, at the kids' pace, bring a GOOD stroller, and we didn't do ANY sit down meals. First time was only 5 days (we had annual passes), and we did enjoy pool time!
For meals, I'd have them sit at a table, then I'd go get the food for them.
Bathroom breaks were usually all of us go if one needs to, but sometimes my son would wait right outside with the stroller for me and DD.
We didn't do everything, but had a great time!
As they got older, I could take one on a ride and have the other wait at the exit with no problem. They know Disney so well, so know what they like to do and what they are either afraid of or just not interested in doing. Most rides it seemed were fine for us to go on together, like when they were really little we'd fit 3 across on Big Thunder Mountain Railroad.
Bedtime I'd get them in their jammies after the bath, then they could watch TV or something.
At the Swan or Dolphin, I'd order kids meals from room service sometimes!