For the party there was never a set time/place to meet up as there are so many variables to attending the party and so many people going.
Some will be going to the park at 4:00 while others later than that. Some who are attending are making ADR's and others are not, some have kids and want to concentrate on the child aspect of the party while others are solo and want to do other things so while we are all attending the the party it will be more of a running into each other party versus traveling together in one huge group like we do at DATW.
I know last year this worked out really well and we all unofficially met near the rose garden for the fireworks. I think that is probably what we will do again this year.
With that said, if anyone wants to create their own smaller groups to tour the party go for it. Also remember, the party is after the cruise so you will meet many folks on the cruise and then recognize lots of people at the party.