My daughter (currently in 7th grade) has attended Girl Scout Day Camp for the last 6 summers, and will be attending again this year. You do not need to be a girl scout troop member to do, you just pay the $10 Girl Scout Registration and you can go to the camp, and that makes you a Girl Scout.
Camp is from 8:30-4:00 daily. Over the course of the summer there are 1 and two week session for a total of 7 or 8 weeks (depends on how the weeks and school calendar fall). This year, I think a 2 week session costs $300 and a 1 week session costs $150. They provide FREE bus service to my town, and the stop is about 1/4 mile from my house...our stop is the first on in the AM, last off in the PM, so she is on the bus for almost an hour each way, but she doesn't mind. When she was little I drove her (20 minutes to the camp from home).
At camp, they hike, swim, do crafts, sing, sports, etc. They are outside all day unless it is raining, then they go into the lodge and do activites in there. Last year, my DD got Red Cross Babysitter Certification as part of one of her camp activities

During the Two week sessions they have an overnight for girls entering 4th grade or older.
My daughter loves it, and usually goes for the whole summer.