The
RDF Sourcebook, which covers the Persian Gulf region, gives an idea of what the authors thought might be possible in an area with enough oil left for military and possibly industrial purposes. How often the aircraft fly is rather another matter. I've been told that modern combat aircraft burn through parts the way an alcoholic burns through a liquor cabinet. My reading on the subject generally supports this idea, although the alcoholic bit might be an hyperbole.
Parts for older aircraft may be easier to fabricate than parts for modern aircraft, but there won't be any assembly lines for P-51 parts. I don't know enough about supporting aircraft like the ones in the Confederate Air Force[1] to make a realistic assessment of how hard it would be for a major cantonment like Colorado to support obsolete aircraft. I don't know how many would be available, even to a major cantonment.
1 For those not familiar with the Confederate Air Force, a brief overview is provided here:
http://www.angelfire.com/ca4/b17/con...eairforce.html