Our group of 6 did this dinner back in December 2001. We had been to Hoop-De-Doo many times and wanted to try something different. We had a nice relaxed time and enjoyed the food, although it was pretty much standard barbeque fare. One of my favorite memories is my mother-in-law, me and Chip square dancing after dinner (fun photo op, too). That and seeing my husband and brother-in-law line dance with Goofy.
The dinner can bit a bit tough to get to if you're not staying at Fort Wilderness. We found it easier to park at Wilderness Lodge and take the water shuttle than to take the two sets of buses.
You walk down a dirt path right by Pioneer Hall and Crocket's Tavern to an open-air pavillion. As you enter, they check ID's for those would would like beer with their meals (otherwise I think it was lemonade and maybe soda as well as water). You then proceed to a couple of buffet lines, where items such as hot dogs, baked beans, cole slaw, cornbread, chicken and a few other items I can't recall are laid out. You then choose your seat from many long picnic tables. If the dinner is crowded, you most likely will share with at least one other group, but the tables are really long. Mickey, Minnie, Chip, Dale, and Goofy were the characters at our dinner, as well as several "human" friends and a country band. We were entertained by 2 human MC's and another fellow who was quite impressive with a lasso. At certain times kids as well as grown-ups are encouraged to head to the dance floor for country dancing.
After a while, a couple of large sheet cakes (with an American Flag) are brought out to the buffet lines-- I think they were chocolate and vanilla with vanilla buttercream.
Hope that helps! We plan to try this again in October when the group goes to WDW again.