I’ve been lurking around your blog for a while now and I love it! I’d like to share this link with you: the Iowa Health and Physical Readiness Alliance  web site.
This online library has several old military physical fitness manuals (dated 1892, 1914, 1917, and 1946). I think that your readers would really love the 1946 manual, FM 21-20. Not only does it have an extensive calisthenics routine, but also has guerrilla drills on carrying wounded comrades, running and swimming instructions, and even brief sections on wrestling, boxing, and hand-to-hand combatives. All are in PDF.
Enjoy! – Tom R.
JWR Replies: Those manuals can be quite useful. But I must forewarn readers: Old School methods of “warm-ups” provide insufficient muscle stretching to prevent injuries. They also emphasize “bouncing” stretches rather than slow stretches. It is the slow stretches that are much safer. (Bouncing can tear muscles and ligaments.) I recommend doing some slow Asian martial arts stretches  before doing calisthenics workouts or running.
Also, keep in mind that these older manuals often depict running in boots. That too can lead to injuries. Be wise and minimize any regular running in combat boots!