Not quite the same, but I've been through two longish enforced layoffs due to injury, including one of six months when I didn't know whether or not I'd be able to get back to running properly. What has helped me each time has been volunteering at parkrun, and at events of my running club. That's helped to keep me part of the running community, given me a focus - and I've enjoyed it.
Have you considered coaching? With 40 years of experience, maybe you could help local youngsters? Not the same, but it might help?
Not sure what to suggest for keeping up the exercise. You might find that cycling becomes more appealing later - at least you can be outside in nice surroundings.
The main structures on the outside of your lower leg are the fibula (smaller of the two lower leg bones) and the peroneal tendons/muscles. Further to the back you have the main calf muscles, and the the front, the muscles and tendons associated with the feet and digits.
You may just have been unlucky and managed to jar/pull something. RICE treatment initially is usually sensible.
Re. dying... What you do need to be prepared for/avoid is hypothermia - and not just in winter, on the hills. Read the reports for SDW 2013 (mine is on my blog (https://runningape.wordpress.com) - try https://runningape.wordpress.com/page/3/ and look for the title SDW - Wet and Windy! I played with hypothermia at the inaugural Greater Manchester Marathon (4 C before windchill, gale force winds, rain, hail) and it's no fun. Having the proper gear for SDW made a real difference (GMM I'd had a waterproof jacket with me, but my the time I realised I should be wearing it, my hands were too frozen, despite gloves, to get it out and put it on).
Beachy Head was great fun, despite the wind. There was one point that the wind was so strong I could only keep going forwards because I dropped in behind someone larger than me and keeping right behind him for several hundred yards until we dropped down out the wind - don't know who he was, and he possibly never noticed I was there, but he really, really helped. The Seven Sisters, near the end, are a real challenge.
Enjoy it for me - I was intending to run it again this year, until I broke my ankle six weeks ago (not even while running!)