Food-wise, I would say try to get the stereotypical food from real camps, maybe? Think: S'mores, trail mix(?), etc. (If you need anything for cakes, I know Pinterest has some cool ideas such as 'campfire cupcakes') If you need any gift ideas, I know The Rooster Teeth store has some great official merchandise (shirts, etc ; you just go the store and use the Camp Camp filter to the left ; I believe they just put out shirts with character silhouettes too) I wish you the best of luck with her party! I'm sure whatever you do, it'll be great!
Idk if you still need this but- 1. Pinetree themed stuff because that's a pretty important symbol 2. Yellow and green colors 3. Sugar cookies with like cane sugar on top (There was an episode about other characters in the show about them accidentally starting a drug cartel with """"cane sugar""""") 4. Popcorn (woodscouts) 5. Purple kool-aid (cult episode) 6. Someth about a platypus