Really good post Northern
Me I have been a distance runner for 35 years and run everyday but spend more time following boxing now than I do following athletics ! So If your looking for an almost 50 year old light middle weight that is flat footed and slow you know where to find me
Or maybe I could sweep the gym floor !
While the OPs fitness may not be up there now it wont take long and your suggestions of using hiking to help bring on the fitness is always too over looked and because of the nature of it ,it is considered to be of no use .
The hiking actully builds the muscle up but importantly trains the system to develop that slow burn of energy required for when the athlete finally makes it upto the weekly long run .
Increasing running distance by 15 % a week should work well with out the risk of injury along with a 6 mile walk to begin with .This walk can become a run over time
You point about joining a running club is a really good idea over the years I have seen amateur boxers benefit from being a club member quite a few times at the end of the day the hardest thing to get motivated for as a boxer is normally the long run especially on a winters day
Back in the 70s here in Cullompton Devon (if you know it) the running club was a boxing /running club and that worked really well