I walk 1 1/2 miles a day with my wife and dog, which is their limit. I recently began a little archery, which I enjoy a lot. If I get good enough I might go for a deer next year. I do a lot of yard work and gardening April through October, stretch and do core almost every day, do presses, curls, pushups etc three times a week. In order to have something to do when cycling isn't feasible, I work in some rucking from time to time. This is simply walking with a weighted pack. In my case I can get 3/4 of a 40 lb sack of water softener salt in my pack,(30 lbs) and unlike steel plates or dumbells it is comfortable to carry. I try to get in a 20 mile bike ride at least 5 days a week, but the winter weather can cut that back a bit. When the temps are in the teens or below (Fahrenheit) and there is some stout wind, I do find something else to do. I find it hard to keep toes warm after an hour of cycling in those conditions. In September 2017 I was riding my Brompton in the rain , found a pothole and broke my pelvis in 3 places. The ortho Doc said to just let it heal as it was lined up perfectly and by January I began working up some bike miles and by March was pretty much as good as new. I mention this mainly because I was amazed by how quickly muscle mass disappeared in my first week afterwards and later, how quickly it came back with therapy and a little work. Sure went faster than coming back, though. This kind of crap is so much easier to come back from if you are reasonably fit and not obese. In fact a doc once told me any sort of health problem is better if you are strong and healthy to begin with.
