Really, the Scouting book has alot of good standard stuff to get into, and the Scoutmaster's Handbook has some great ideas. Newer Scouts have alot of level requirements to fulfill, you can kill off a few of those as part of your curriculum. Depending on time of year, improvising shelters is a great group activity, and kids can put something up and sleep in it. Plant and animal identification too - go on a walk and find 10 of each, what few poisonous plants to look out for etc. Something as simple as knife safety and sharpening their knife can get them onto their Tote n Chip and contribute a valuable skill. Maybe a primer on building a first aid kit and cleaning and dressing simple wounds.

Keep the talking to a minimum, hands on as much as possible. If the kids have been on campouts, hopefully the adult leaders have related what they carried to what they need to survive. If not, a few minutesw on the rule so 3s etc and the importance of going out prepared.

Consider having a few stations, and rotate the kids among them after an hour. Depending on how many kids you have, a larger class can be hard to handle and sorta boring for the kids. No matter how involved what you have to say may be, few if any kids will want to sit there all afternoon hearing about it (unless it eventually involves exciting stories ending in missing limbs and digits). Smaller groups working 2-3 together can get alot more done. Fire-making seems to be popular among kids and adults. Combine it with an hour on backcountry cooking, and have one group prepare lunch for the troops, another make dinner.

I recommend you involve your other adult leaders directly in whatever you do, if they lack experience get together with them beforehand to practice the skills you intend to cover, then have them cover a station instructing the kids. Don't make them students for the day, let them lead some of the skills, even if they aren't expert. My first time out with Scouts I was impressed that every adult leader knew so many knots (more than me), little did I know that a few of them had learned them just the week before the outing.

Last I would tailor this to the audience - if they're urban / suburban kids then cleaning game is overkill as a primary skill, if they come from hunting families they may already be familiar.