http://www.cleverscampcamp.com/cinnamon-bay-camping-usvi/

Camping in St John USVI?
I am thinking about camping in St John SUVI in october. I really want to stay at Cinnamon Bay Campground. Has anyone been? Where do you get food? Did you rent a car? I’m going alone is it safe (I am a female)? Any tips?
Cinnamon Bay has an on site general store, for your basic necessities as well as a restaurant. If it’s just you then you could probably get away with $20 a day to eat. Stop at a store in St. Thomas before getting on the ferry to St. John and get a jar of peanut butter and a jar of jelly and a loaf of bread. PB&J doesn’t need to be refrigerated. That’s if your going for a bare site ($30 a day). The beach shop also rents snorkeling equipment.
You don’t say if your renting a bare site or if your going to take one of their ready to go campsites. IF you choose to take theirs it comes with EVERYTHING you need for around $80 a day, which is a deal for St. John plus you don’t have to lug a bunch of stuff there and back. You’ll get a cooler and a stove plus a cot and lots of other stuff. If you get that you can do a little grocery shopping a buy a few things to make. Pasta and sauce, cans of chef boyardee, lunch meat, cheese. Pack some zip lock bags in your pack, use them for your lunch meat, cheeses or anything you buy that can’t float in melting ice! http://www.cinnamonbay.com/tents.html
You don’t need a car, you can get a taxi from the ferry dock to the campground. Once there you will find great hikes to other beaches plus if you want to go into town you can just catch another taxi.
I’m going to suggest an alternative to Cinnamon Bay, it’s Maho Bay.it’s a privately owned eco-resort they have tent cottages for $80 a day, they also have restaurants, a store and more. It’s a great place and since it’s privately owned and operated it is going to be a lot better maintained than a public campground. It’s also within hiking distance to other great beaches (assuming your in reasonable shape). here is a link to their site, check it out and weigh your options. http://www.maho.org/maho.cfm
I wouldn’t worry to much about traveling there alone. Just use common sense and keep alert. If I was you I would carry a small can of pepper spray, you never know what can happen and it’s always better to be prepared even on a quite safe island like St. John.
Snorkeling Cinnamon Bay – St. John, USVI