I applied for official Adopt-A-Highway status from the Kentucky Department of Transportation, and our local Campaign For Liberty group adopted two miles of Richmond Road in Lexington. We've had three open carry litter pickups. I've been 100% ineffective in getting any local media attention other than Leland Conway on 630 WLAP... thanks Leland!
IMO, you don't need official Adopt-A-Highway status to be a good citizen and pickup litter, and you certainly don't need permission to open carry on public property. The Adopt-A-Highway signs are nice. If you go that route, try to get them to put something like "open carry" or "gun rights" on the sign as part of your organization's name, because those signs are educating people 24/7.
Here's our website for the open carry litter pickups.
http://www.GunsAndGarbage.com
My contact info is on that website. Call or email if you have questions or comments. Let me know how I can help. I'd be happy to post your open carry events on the website, and I'd probably make the trip to Louisville for an open carry event. Maybe several of us in central Kentucky could carpool to Louisville, and make a day of it, with an open carry dinner as well. The Kentucky Kel-Tec Owners Group just had our quarterly Knob Creek shoot and when we finished shooting, we had a nice open carry dinner at Tumbleweeds in Valley Station on Sunday evening.
We also have an open carry picnic in the park coming up soon in Lexington. The city is still hassling me with some bogus insurance requirements (almost certainly a bureaucratic policy that's being selectively enforced), so we can't publicly advertise the open carry picnics. I invite all of my liberty loving gun nut friends via email. Are you my friend? Send me an email!