I was about to write that it's not a lot - but it's all relative.
I hadn't planned on running that morning, and when the chance came up in the evening, I took it.
I only had about an hour, so I ran as far as I could in that.
And while I was mentally grumbling that the music in my headphones was hard to keep up with, one of the characters in my story explained why they wanted to see Penny, my central character. Then Penny gave her reaction to the meeting, and the kind of request a character should leap at in a story. Then everything kicked off in the setting of the bricabrac-infested flat Penny hides away in.
So it was just four miles, but when I look back on how far I've come, it's a long way.