Last year they shifted dates at the last minute. It ended up being Monday & Tuesday I think. The actual parade filming is one day but then there are the spots they do in front of the castle and in other areas.
I've been there at that time, it's really not a big deal. It's not as great as it sounds, the parade doesn't march down Main Street and it's over in a few minutes. It's an all day taping. They film it various ways, one float at a time, and then they will do a couple runs of it in normal time. They also film the hosts. The last time I saw it in 2009, we were sitting on the porch at Tonys while Kelly Ripa was filming the closing with the Dalmatian dogs.