My DD (she is 11) is a ridiculously picky eater. I am always so embarrassed, like I have failed as a mother, considering my DH and I are the opposite of picky eaters! We love all food and all ethnic foods, vegetables, meats, etc.
Biergarten is a MUST DO for us almost every trip. My DH loves the huge beers, and all the meats on the buffet. I love the atmosphere, entertainment and of course the food, too. My DD LOVES the entertainment...and she loves the food, too! She always gets the pork schnitzel...it is a very white pork and crispy and I swear, it could probably pass for chicken. The mac and cheese is also great...and yeah, she does like the bread and I don't mind if she fills up on it. I am not going to say we get our money's worth...but with DD, we NEVER get our money's worth at a buffet. Of course, her dad and I make up for it, LOL!
The only one who *might* be bored is yor 14 year old. DD is just now feeling "too cool" to go on the dance floor, which kills us, because she has been out on that dance floor at least once a year since she was 3. Honestly, your 4 year old will probably have the best time of all!!!
Have fun!