I wrote this on a different thread but it seems relevant here.
Here is the deal - you plan like a banshi, then you plan some more, then you change your plans and modify ... you eventually get exasperated and throw your hands up in the air thinking, "We are screwed". All of this planning however is a learning experience. You start to internalize things at WDW. That knowledge in and of itself prepares you to be more flexible in your daily routine once you get there.
The beauty of planning is not that you have to follow some order moment by moment. The beauty of planning is that you are better equipped to adapt as circumstances arise. The beauty of planning is the information you learn in the planning process. Nobody likes unpleasant surprises; they tend to ruin an otherwise ok experience....and if you don't plan and learn you for sure will have several unpleasant surprises on your trip.
Example: I used to be a professional musician and songwriter. I would practice the same musical scales at extremely slow speeds, highly disciplined, no originality, no emotion, and no fun. All work. Other musicians would rag on me for being an uptight guitar and song writing nerd. When I put together a show or concert we would play the exact same thing over and over and over again until we could play it with our eyes closed with earplugs so we couldn't hear. Now that is disciplined planning with nothing fun or spontaneous about it. But the result of that planning is it made it extremely easy for us to go off into musical solos and wail. The result of all that uptight planning was more spontaneity, greater flexibility, greater ability to adapt to others' mistakes or technical glitches, the ability to be freer to improvise, and a mind-boggling level of fluidness.
We had a saying - SPONTANEITY COMES WITH PRACTICE.
After all, if the G string on your guitar flies off and smacks you in the eye and you built 1/3 of your solo around your G string and now you can't see...you are in deep trouble unless you are so well versed that you can close your eyes, adapt, improvise and wail like a mutha while shifting your entire solo into a one handed solo so you can continue playing effortlessly while you simultaneously change your string. And that kind of spontaneity doesn't come from being a free spirited undisciplined person all the time. It comes from practice and planning. It is the difference between not knowing how to adapt to a negative situation, or being able to take any negative situation and with ease turn it into a positive. Its the difference between boos or screaming fanatical applause.
It isn't fanatically sticking to the plan that matters. It is the process of planning that matters. It is that process that gives you the insight and ability to adapt, to be more flexible, and to be more fluid, and paradoxically to be more spontaneous.