We did it Wednesday, and the weather royally screwed us. Short answer: cancel it. Except for the dessert party, you can experience everything else in the exact same way and save the $60.
Procession: Reserved seating is good, but you have to get there before the posted 10 o'clock check in if you want to actually be in the front rows of people. If you're going to wait an hour anyway, there are plenty of other spots to choose from. If it rains and the event is cancelled (as it was on Wednesday), you're out of luck.
Sing along: Again, when I checked in at 10, the early shows were already either gone or nearly so. We ended up with 3:30 tickets. We were seated in the 3rd row, but, again, if we had gotten there at 3:00 for standby (instead of the package), we would've had fine seating in the theater that wasn't reserved. (We also discovered that the first two rows were reserved for handicapped, which is fine, but if they don't fill them with HC, they'll put in late arrivals. So basically, the big head in front of me came at about 3:20 for the show and had a better view than I did without paying the premium price. It seems that sometimes they'll fill the rows, other times it's reserved for VIP, so I guess we just got unlucky.)
Dessert party : Delicious desserts for sure, but really...how much can you eat? $60 worth? In about a half hour? We were moved inside due to the rain, so they let us in at about 8:35, let us stuff sugar down our throats for about a half hour, and moved us to the reserved area at 9:05ish. It was speed eating/drinking at its finest.
Fireworks: Great view of the show, terrible view of the fireworks, as they are just about entirely obstructed by the stage. You're better off further down Hollywood Blvd (closer towards the entrance, near Keystone Clothiers) or even Echo Lake to actually see them. In fact, most of the reserved area was cleared out as people moved to get better views at that point.
We went to experience it twice, once with the package and once without. Granted, the day we saw it WITH the package it rained all day and we didn't get to see the procession, but honestly it wasn't worth the price vs the experience without it.