I am a 2nd year head coach who has run my own camp the past two summers for my team. I coach only the girls, so the gender thing is not an issue. We rent condos that sleep 8-10 people each. I have 1-2 adults per condo (they are the drivers more than they are actually "chaperones"). We go for 5-7 days.
With a little guidance, the kids are pretty good at helping out with things like food shopping and cooking.
BIGGEST PIECE OF ADVICE: if you assume they have any common sense at all, even the common sense that a kindergartener would have, you will get into trouble. Example: in the first year I had my runners go on a simple out-and-back run. They ran down the dirt road; at a designated time, they ran back up the dirt road. Simple, right? Apparently not, because I had a group of them (even including some upperclassmen!) who took a left off the road and kept on running for over an hour in the wrong direction when they had only gone 20 minutes out, thereby making it obvious, if it wasn't before, that they were headed the wrong way. I think they would have kept going forever if we hadn't rounded them up with the cars. So basically, keep an eye on everyone like you would if you were babysitting, and you will be okay. It makes your runs more boring, as you pretty much have to keep the kids in view, but it beats being fired or sued. Good luck!