Craigslist is the best thing to ever happen to classifieds. people will put stuff up they never would have spent the $50 the newspaper wanted for an ad. it also beats ebay for anything to big for normal "stick it in a box" shipping. I only wish they got rid of their stupid no guns policy. For that I have noticed some areas have facebook groups that also do classifieds. Some good cars on there and they also will do guns. You just need a page with at least about 2500 followers that is specific to cool stuff. My town doesn't have a good group but a smaller town a few hours away has an awesome one. Both craigslist and facebook is probably no good for the old guy who doesn't have a computer or camera, but most of those guys will ask a friend or a grandkid to help them out.
I have knocked on a few doors and I deliver mail for a living so I see lots of cars. Still I only find people who are going get around to it. Maybe they would sell, but never seems like a good deal. Craigslist on the other hand the people are ready, you have to be ready as well because a good deal will go within hours and you never even see them if you are only checking every couple of days. When I'm in the market I will check every couple hours during the day.