All of the farmers can refuse to sell to them. Quit frequenting any central Maryland business while there for work... pack a lunch. Establish a western maryland association and charge a toll to cross South Mountain. Choke the bastards out. Let the core rot even more and establish free zones.
Just ideas.
When you say "free zones," I think getting rid of firearm pre-emption(?) and letting the individual counties decide what works for them. I can imagine the nightmare that would be keeping up with each county's laws though.