John,
We were there for those cold nights and days and we found the parks to be great very early and very late.
First night we were there we went to see the Osborne lights at DHS and I went into it scared thinking we would have wall to wall people like so many people described here. Instead, we literally had the place to ourselves because there were so few people. It was awesome.
The next morning we forced ourselves up early and got to the Magic Kingdom at 7:30 (eventhough we were not staying on property they let us in) and it was eerie how empty the park was until 11. After that it was chaos, but for those few hours we walked on Space Mountain, Buzz, Big Thunder, Haunted Mansion, Peter Pan, Snow White, Pirates, and Jungle Cruise.
Couple of days later we caught the boat across 7 seas lagoon during Wishes and when we got there the exodus out of the park was crazy!! We forced our way in through the crowd leaving (they all looked cold) and found the park to be very nice. We had a big empty space around us while we watched the MSEP. After that we just about walked on every ride we wanted to until 1 am.
For us the cold weather did a great job of chasing people out of the parks.