Walking, or running, is good for your brain in almost every way. My depression was/is coupled with social anxiety so it was hard to get myself to do it but things like walking to the grocery store instead of biking/car helped me change that into 'I'll take a detour'.
The worst hobbies for me are the ones that are done sitting still, or anything that 'creates' a different 'reality/world'. For me that was anything behind my pc. Woodworking is better for me and allows me not to worry about social stuff but walking is definitely better for my brain.
I adored my HP Veer, I bet that if I get a working one in my hands I'll blind-type flawless again in seconds, I was better on that thing than any full size keyboard. Best phone I've ever had because of the keyboard and the ease of customization when you know Javascript. Screen was a bit too small (I consider every modern phone way, way too big) and speed could've been better but wasn't bad.