I think, especially with young children, park hoppers are a must.
You can escape the busy park if it is getting too much, but you won't feel bad, cos you can always go back later, or try a different park, or rest for a bit first. It Just makes everything a lot more flexible, and that has to be a plus with a small child.
I totally get where you are coming from on the planning. You need to know SO much before you go to WDW, it's crazy. it is something I really think is a negative to the whole experience if I am honest.