I have not been to the Backyard BBQ but have heard that the food is not cooked outside. For example, I have heard that they serve those steamed hamburgers which I have tasted and are terrible.
I suggest that you go to Outer Hanks for the best deals. For example, for $9.99 you can get a half a slab of ribs and fries which they just pile into your basket. They were delicious too. Outer Hanks also has good seafood.
Skyline is not a bad deal either for park food prices. You can get a big plate of chili and spaghetti for just over $6.
I also love Potato Works which has been at the park since it opened in 1972- everyone brags about CP's Boardwalk fries but the Potato Works fries cannot be beat. They also have other nice goodies to nibble on such as chicken bites and shrimp. The price of fries may seem high at $5.99 but you get a huge amount for the price.
I used to love to go to LaRosa's when I went to KI but the quality has really gone down there over the years. Their slices literally have declined in size by half while the prices have gone up. ( $6.17 for two slices. ) And for some reason, their idea of a slice of pepperoni pizza is maybe 2 pieces of pepperoni per slice-it used to be that they would pile on the pepperoni.
Also, I tried the buffet next to Diamondback and the quality of the food was way below the outrageous price of $16.95.
Once place KI hasn't gone downhill is dessert. I still think their soft serve ice cream cannot be beat. It is $3.74 for a cone, a little pricy but not horrible.