Trying to figure out where these mostly small installations are is an enjoyable map study project. Much like what we had to do in mineral exploration field work: Job #1 is locate and sample old production.
To add a bit of historical background, my wife's maternal grandfather was a flyer so much from the old school that his initial flight training was in balloons during WWI. He shifted to fixed wing piloting and flew the mail across the West for some years in the 1920s. He had a number of forced landings and was reported missing for several days on 3 different occasions. In 1928 he was hired to fly Ford Trimotors for the predecessor to TWA, an erstwhile operator named Transcontinental Air Transport. Starting in 1929, TAT had an odd New York to Los Angeles passenger flight plan: a 48 hour trip with flights by day connecting to trains by night. TAT was derisively called "Take A Train". A merger formed what was later renamed TWA in 1930 and all-flight transcontinental scheduled passenger service began in that year. Captain Earl Fleet flew for TAT and TWA until the late 1950s, the last few years assigned to the over-the-pole San Francisco to London route in 4-engine Constellations, one of which he emergency-landed (engine afire) at a former bomber base in Cut Bank, Montana very late in his career. Captain Fleet was one of those guys who combined flair and fearlessness with daring which he exhibited by always driving Cadillacs and driving 100 mph pretty much everywhere he went, even in retirement.
