Some additional data. WNYC, using publicly available data, and and assuming a 2200 NM range, found 634 airstrips 5000 feet long available. Interactive map at:
http://project.wnyc.org/runways/?utm_con...campaign=buffer

A lot more than I would have guessed, and some in pretty out of the way places. . .
_________________________
"Better is the enemy of good enough."