I found that walking in the alleys in my neighborhood was a lot of fun. See all kinds of things. But, it can be dangerous and people are suspicious with good reason. I live in a
good place in a bad city.
I've been on my feet, knees or hands and knees my whole life. I have probably sat at a desk in my whole life as much as an office worker does in one year. Don't try to calculate that, it's just a point I'm making. I've worn many joints out and had one replaced. That's enough of that.
4 miles seems like a lot. Anyway, unless you change venues, it gets boring.