I don't run competitively anymore, but had a pretty good stretch on the roads where I was able to run at some US championships, get free shoes, clothes, gear etc, so I know what you mean in that it is a hard void to fill when you are used to brutal workouts and 100+ Mile weeks.
For me this balance of activities has worked so far and allowed me to stay pretty generally fit and happy:
- Running about 60mpw but keep it on mountain trails so it is more fun and unstructured (year-round)
- Hiking about 10-20mpw with my wife and dogs (year-round)
- Backpacking/Camping (later spring-summer-fall)
- Skiing1 weekend day and either a half day or night during the week (winter-spring)
- Clay Shooting/Hunting (summer for shooting into fall for upland bird hunting) this actually requires a good bit of hiking too
That keeps me pretty happy. Some weeks I will run more and some less. This has kept me fit and healthy without the stress of hitting every workout, or every session or not feeling pressured when you have to take a day off for work, or travel or life.