battling the hills where we live (in the Hilltowns of western Massachusetts, or foothills of the Berkshires).
Just out of curiosity where are you? Berkshire native here (and still here!
North Adams as an undergrad, Great Barrington for 20 years, now currently in Pittsfield. Friends in Monterey & Otis.)

Is this a mid-life crisis thing, or more of a permanent insanity?
Maybe a little of both? Not so much a mid-life crisis so much as a mid-life reawakening. I began cycling off & on about 10 years ago after a squillion years of not doing it. Began doing it more seriously about 3 years ago. Even more seriously last year after having knee surgery and the orthopedic surgeon recommended cycling to strengthen my leg. Have my eye on a Specialized Vita come spring.