I'm a TGM'er planaholic, too. And I love it! Planning is the best way that you can squeeze the most attractions into your trip.
That said, I also plan for some downtime or a day "off" from the parks so we can relax to soak up the magic and do some spur-of-the-moment things.
I don't use a spread sheet. I use index cards.
Dh was skeptical about my plans, but once we followed them he said that I did a great job putting together our trip. He was impressed with how well those little cards led us through our day.