Superb writeup. One note; a good compromise between entertainment & into and situational awareness might be a single earbud with the radio set to mono. You'll get all the content while still retaining the ability to focus on outside sounds.

Again, I commend you on "letting rubber meet the road" and trying out your GHB. Many guys will "wargame" their pack but never try it until they need it. It was wise to give it a trial run.