We also did the Backyard BBQ in April 2000. While the food was ok, my DH had no problem making sure he got his fill, when they say "all you can eat", they mean it, definately plenty food and beverage (both soda and wine). The interaction with the characters was very good, in fact our DS's enjoyed the characters there better than in the parks (much more time). The country band was good but a bit loud, but with a little cotton to remedy the situation, all was well.
The games are old fashion carnival games, nothing fancy, but the kids enjoyed them (they were 2 & 4).
The best was the family picture they take before hand (even though the 2 year old was sound asleep in the stroller), but none the less a really nice momento.
Also plan on meeting lots of people from everywhere. The seating is rows of long picnic tables, you sit where ever.
Have a great time!