I might be going to beirnheim forest (sorry for misspell) tomorrow looking for branches and trees if I'm aloud to take a couple
Ask the property manager if you can cut something that is non native (like Osage ) or a nuisance species like black locust. Tell him what you're trying to do and maybe he'll help you out. Plenty of good wood in that area.
If anyone has suggestions on a meeting place that is agreeable , then load the tools, benches, wood and rock and make a day of it

Tracy