Definitely pajamas/robe that you don't mind campers/staff seeing you in. This was the most annoying thing on my packing list since I'm a "less is more" kind of sleeper, so it always takes me the entire first week of camp to get over the sensory aspect of sleeping in pants.
The camp I'm at is electricity-free for all camper areas minus infirmary and where we eat and an office, so I suggest a head lamp instead of just a flashlight if you'll be similar. This way you still have both hands usable in evening and night if walking around. I wear mine as a necklace for the most part.
I'd check where the nearest "wal-mart" is. I drive 11hours to camp, so I don't bring 2months worth of stuff in my car. Nearest store is about 30min away, so I stop there during pre-camp to stock up on what I need. This year I have Amazon
Prime so I plan to just free ship a lot of things directly to camp (ie: my dog's food, shaving creams, shampoo, etc).
I'd bring a couple pairs of shoes.
I take GOOD rainboots (our camp os full-force no matter the weather. I have a nice pair of Kamik rainboots that have lasted me 3 years. Fellow nurse had ones from Target and they fell apart after getting stuck in the mud a few times)
2 pairs of sneakers incase one gets wet mid day.
Trail/hiking sandals (Chacos)
Regular lounge-y sandals.
I go up to Maine from the Phialdelphia area, so I pack more clothes just because I can be wearing pants until 10am and then in shorts rest of day because the weather fluctuates so greatly. Camp does laundry once a week but I have access to the director's washer if I would really need anything cleaned in a timely manner.
I like to have some hobby stuff with me, too. Coloring books, reading books, cards (I do paper crafting), to kill time.
Also something to do on a boring or rainy night with fellow staff. A fun card game or something. There's been years that I never touched what I brought, and others where it was a weekly event coming to my cabin to play Apples to Apples.