I was a BM in my good friends AHR this past weekend and everything was very nice, but I wanted to drop some knowledge here for lurkers.
Regarding the dinner buffet:
The bride had about 300 people at her AHR, but only 1 buffet. The caterers were serving the food, so only one side of the buffet was open. The bridal party got there around 6:30. Head table was released to buffet just before 7pm. My DH was the 3rd to last table to be released and didn't get to go up to the buffet until 8pm! Not cool! I also felt EXTREMELY uncomfortable eating at the head table while all the tables around me had no food. I felt like everyone was staring at me with hungry eyes.
Moral of the story: if you have more than maybe 150 people (maybe more than 100) you really need to have at least 2 buffets. Ideally 2 buffets with both sides open. The food was delish and there was plenty of it, but it was awkward when I was finished eating and finished my dessert and DH still hadn't eaten.
I know some things can't be helped and obviously when you have a big reception not everyone can eat at the same time, but I think within 10-15 minutes of each other is acceptable. 1 hour later is not acceptable.