Randy,
I personally don't know what may be available in the area but you may have some luck calling suppliers in the area such as NPD, Virginia Mustang, Maryland Mustang, Laurel Mountain Mustang, etc. They sometimes have the inside track on cars for sale or may have some tips about local advertisers that specialize in Classic Cars and think there is even a Classic Mustang Only Classified Magazine available.
See if there are any Mustang Clubs in the area; they may have some leads for you...and I suppose you could place some ads yourself in local news publications, possibly Craigslist, Hemmings Motor News or through the Mustang Club of America.
Rust free cars may be a bit tougher to find on the East Coast but there are some I'm sure. Otherwise your best bet would be dry states like Texas, Arizona and California.
Good luck and hope you find something. I'll let you know should I happen to hear of anything.
Ray