Not long ago, I had dog that got loose and went out to 'explore', only to get lost. He was gone for over 10 days. I know how you feel.
I would recommend the following, in addition to the paper ad (hopefully in the TD AND the CourierJournal), flyers, and door-to-door checks you've done:
--Go to your City Hall, and find out where your meter readers (electricity, gas, and water) report to work. Post a flyer there, and highlight or WRITE IN BIG LETTERS your street name and neighborhood so that it will get the attention of those who work in
your specific area. I would also suggest that you speak with an office worker there and make copies of your flyer along with a hand-written note and leave a copy of each for all of those readers who work in your neighborhood. In my case, I actually arranged to be there at the beginning of a shift and spoke with a few.
--Contact the city's street and sanitation departments and do the same. Try to get a flyer and note to the people on the crew(s) that regularly work in your neighborhood.
--Be sure to do the same for your mail carrier if you haven't already.
--I actually made a "Wanted" ad, made a few copies, and took it to my local police station. My dog's mug under the huge heading of "WANTED" got their attention because they thought it was so funny. They posted one on their bulletin board in the main office area and told me they'd get the copies to those who patrolled my area the most.
Basically, be sure you get the word out directly to those people who travel down your street and through your neighborhood regularly, if not daily. I'm sure you've posted flyers on sign posts and utility poles in the area, but that might not be enough to get their attention. Try your best to contact them as directly as possible. Also, be sure to take flyers to any businesses around your neighborhood, the gas stations, and have them posted in the teachers' lounge at any nearby schools.
By the way, in my case it was one of those "WANTED" flyers that led to a 'sighting' of my lost dog, followed by a call to me. I went to where he was last seen and found him within a couple of blocks from there - hungry, thirsty, tired, and really really happy to see his best 2-legged friend!
Keep in mind that at this point, there's always a good chance that someone might have taken such a cute thing into their own home. I mention that because it's a better situation than those "worse case scenarios" that can cross your mind when you're worried. And while it seems logical that they would check the Lost & Found section of the paper, not everyone subscribes and not everyone thinks to do that - believe it or not. So by getting the word out to those who frequent your neighborhood, you might find someone who has seen him in another nearby location since then.
I hope you find your pup soon. I'm sure he misses you as much as you miss him.