The thing is though that most people don't spend the extra money for the parties to ride rides, which they can do during regular park hours.
Yes, I understand that, and rides weren't necessarily our intent either when we were planning how we wanted to spend our time at the party. We only did five rides (pirates, haunted mansion, big thunder mtn, buzz lightyear, people mover), which were walk on with the exception of Buzz that had a 15 minute wait or so if I recall. Everything else we did was party exclusive.
The walkways were not crowded anywhere in the park outside of Main Street and the hub during the shows/parades, but we were still able to get great spots for both. For Holiday Wishes, near the tomorrowland side plaza gardens, and for the parade, about halfway down Main Street in front of the Emporium.
It didn't feel oversold to me, and we were able to do everything we wanted, outside of a few character meets because we weren't willing to spend so much time in line. It was disappointing to miss Jack Skellington, but it was in the high 80s that day and even my 11 year old, who is a huge fan of Nightmare Before Christmas, didn't want to wait for three hours for him to come out at 7pm.
Obviously, opinions on crowd size are going to vary person to person, but for us, it didn't seem like a problem at all. If we did nothing but party shows and the parade at the Christmas party, we'd have been done within a couple hours, or spent a lot of time standing in character lines.
I can only hope that if we end up at a sold out party for Halloween (which I don't think we will during our week) that the crowds are as manageable as they were for a sold out
MVMCP.
**editing to add, we were at the 12/18 party not 12/22 like I typed in my other post, but it was also a sold out party.