I don't know where you would want to volunteer, but we volunteer in Virginia and Maryland state parks with our two daughters. They are currently 10 and 7 and we have been hosting for 4 years.
We just take them with us when we do our running and they have picked up on all the tasks. They can do quite a few of them without us having to assist now and I am sure your son will pick up on many of these same skills.
Our tasks in Virginia are completely different than our tasks in Maryland, but they are both a lot of fun.
PM me if you would be interested in the Maryland gig, they are always looking for hosts and they start in April and go until November. We only volunteer for a one month stint.
