Disneyland
Do you have to plan your after camp adventure before you go to camp? Also anyone going to Disneyland or has been to Disneyland?
I really want to hope I make friends at your camp cause I would hate to go by myself. Unless anyone wants to buddy up and go together 🙂
I spent 3 days at Disneyland and California Adventure Park before camp the first time I went. It was a lot of fun, even though I only had company for 1 day of my visit - but how can you not enjoy yourself at Disneyland 
 Also, I'd recommend to keep your post-camp travel plans pretty open. You never know what you'll discover when you get to the States, or who you're gonna meet!
I was in Disneyland, Anaheim last year - absolutely amazing. I have been several times and must say, they keep the park really updated.
The staff are really friendly (I think they are paid to smile), it is kept immaculately clean and the rides are fantastic.
You will need two days at least - one in each of Disneyland and California Adventure Park. They sell a two day hopper pass (available at a discount online) which allows you unlimited access (you can come and go) for two days between to the two parks. They are right next door to each other.
My favourite ride was Soarin' Around the World, and have had it on good authority that California Screaming is 'the best' rollercoaster there is! I was just a bit too chicken 