Kids are the secret weapon for access on private land!! Don't be afraid to knock on doors and ask to hunt, lots of folks still say yes.
Consider a turkey hunt too, it's exciting and pretty low pressure.... If you blow it on a turkey you can usually find another to chase around.
Pm me if you want to talk more specifically about places to go or tactics.

Have your son knock on doors and ask permission with you by his side

I was pretty amazed at the people who said yes to him at 9-10 years old. In my opinion turkey hunt is by far the best first time youth hunt and permission for dumb birds will be easy with the little guy!!