Talk to your local churches and find out what they have done in the past for Vacation Bible Schools. Each year, there is a different theme and I'll bet there is at least one program, or a combination of several programs, that will gel with the Survivor theme. Especially the food...lol...
Do you have any seamstresses in your group? Have them make different colored arm bands to resemble the buffs worn by the Survivors. Have each class make a different design for the buff and use it on their class flag. That way you can use the same colors over and over.
Survivor begins again next week, so watch the first few episodes and get some ideas from them. Their challenges usually consist of giant puzzles, relay races, etc. It shouldn't be too hard to make the actual challenges kid friendly.