Here's a tip you may not know of. When you want to look beyond just your local Craigslist and you don't want to go crazy searching the CL's individually in city by city, use the SearchTempest search engine designed specifically for CL. Using that, you search all of Craigslist adverts based upon you setting a radius from your zipcode. If you set the radius big enough, you'll be able search all of the US quite easily.
Here's the site:
http://www.searchtempest.com/ When I was looking all across the US for a Mini several months ago, I found a lot of cars for sale on CL that did not appear anywhere else. Meaning these cars were not on MiniMania's very useful Minis For Sale site.
I search for "Austin Mini" and then separately, "Morris Mini". If you just try "Mini", or "Mini Cooper" the results are useless in a search for classic Minis as they include thousands of modern MINIs.
Good Luck in your search.
