I hear what you're saying. This year we decided to run 5 weeks of our traditional day camp (which is usually 8-9 weeks) and the last three weeks will be smaller specialty camps requiring less staff.
Most of our counselors are return staff (thankfully) bit we have had good luck with Craigslist, much more so than with posting at local colleges or in the paper, which we do as well.
As for keeping things more camp like:
1. Sing camp songs, a lot
2. Keep the campers in groups assigned to one or two counselors
3. Stay outside as much as you can
4. Play group games
5. Play camp wide games
6. Have special events; small carnival, makeshift campfire with skits, songs and stories, puppet show, etc.
7. Have activities or classes that campers can choose to attend for the week; crafts, drama, sports, drum circles, puppets, film making, swimming, etc.
8. Have a theme each week (this is huge).
9. Bring in Special Guests; animal show, magician, pirate troupe, theater group, etc.
