To be fair, my first trip was way back in the 70s and I'm not sure anybody had their park visits all that well planned out.
After that, two things that saved the most time and headaches when my kids were little that I learned on the fly:
1. Rope drop as mentioned.
Look, I know it's vacation and you want/need to relax, but if your kids are little I'll bet they're up at the crack of dawn anyway. Feed em, get them to the parks and take advantage of that soft time in the first couple of hours.
2. An afternoon break aka staying on property
Again, thinking about the family with small children. So, you rope drop with your 2.5 kids and get them through lunch but they're flagging ... because that's what kids do. Heck, you're probably flagging too unless you're one of those bloody marathon people. So hop the monorail or bus at about 1 or 2:00, head for the resort, prop your feet up, cool off with a nice snack, maybe take a dip in the pool or feed the ducks or whatever and then head back to a park for dinner and a couple of hours of early evening touring.
Honestly, after many visits my two favorite times to be in any of the WDW parks is the first couple of hours after rope drop and the time between dinner and park closing.