Midlife? I'm 19 and my most common response to depression is biking 15km in any direction.

On the bright side, I've seen pretty much every small town in a 10km radius*, and I found this awesome little trail where a group of nature enthusiasts put up signs with information about local wildlife every 2-3 km. They've been there since the mid-90s, with no website, no roadside marker, just take the trail up behind the Autobahn and suddenly there's 4 paragraphs about Passer domesticus. Not to mention all the breathtaking Danube trails I found in rural Austria, when we spent a week in the Wachau.

* I'm a cyclist, not a mathematician