Be sure you visit all places in your area that pick up strays. Make sure that you visit in person and make them let you see ALL the pets that they have in the building. Including the ones who have been PTS. I have heard stories of lost animals being PTS because they were in an area away from the public and the owner didn't check. Don't trust the shelter! If you're going to contact any government org, calling is ineffective. They're much more likely to pay attention if you come in person.

Make your flyers big and eye catching. Put "Reward" in big, red letters. If you have a significant population of people who do not speak much English nearby, post signs in different languages. Make sure the picture is clear and large enough to see. If he's nervous around people, make sure you tell people not to try to catch him, as that could make him run further away and hide.

Distribute flyers with his pictures & your phone number and go door-to-door handing them out to neighbors, give them to people on the street, and give them to local businesses - pet stores, groomers, veterinarians, grocery stores, etc and make sure your alert all local rescue organizations.

If possible, ask friends to help you look every day in the surrounding areas. Call and shake treat bags. Something I noticed is that if you open a can of food and tap the lid on the can, it makes a noise that sounds a little like a can opening up.

Set up traps in your surrounding area and bait them in case he comes back home. Check them several times a day.

It's a long shot, but there are a few dogs in the US trained to track lost pets.

He hasn't been lost for very long. If you are very aggressive, it'll increase his chances of being found exponentially. I will be sending prayers to Dean and you. Please come home Dean.