The things I think about when I run

Running path on the Meewasin Trail in Saskatoon.

Sometimes when I run on the streets of Forest Grove I'll catch the smell of meat cooking on a propane grill behind the opaque fence of some house I'll never visit.  The smell is borne of the meat, and it snakes over the fence slowly like a cloud until it reaches my nose and I breath it.  It originated from the thing it smells like, and as I run through it, I try to focus on the fragmented memory it evokes--of a time long ago, when I was a boy at summer camp, the hot days, the hot dogs, the unpalatable smell of chlorine, the fresh dirt kicked up by my tennis shoes and the thrill of a Friday night camping away from home.  All these things fit together perfectly and rationally in this fragmented memory, (a once perfect memory). And yet it's hard to know exactly what I've forgotten, or why my neural pathways choose to remember the scent of grilled hot dogs; and not, for example, where I left my blood sugar meter.
My summers at camp are such a surprising thing to think about as I run on the winding streets of the neighborhood.  
One thing I do to get myself through runs if I'm tired is to imagine I'm nearing the end of a marathon.  In this reverie there are lots of friends, former coworkers and maybe even some neighbors--all of whom are genuinely surprised at my running ability.  I've never bothered to analyze these waking dreams.
I never dream of running when I sleep. 
When I would run along the East River in New York City, I would often distract myself by listening to sports radio.  Sometimes I would listen to podcasts as I crossed the Williamsburg Bridge into Brooklyn.  (My god, that bridge was tough.)  It's really too bad that the bridges here in Saskatoon are not suspension bridges.
Where I am doesn't seem to matter too much.  Even when I've run in the desert, the basic reality about running does not change. If I don't think about my breathing, for example, it won't be an issue.  I don't often stop to take photos... I don't often stop at all.  I like to maintain the intensity all the way through the run.
If my muscles are too tight, I try to focus on just putting one foot in front of the other.  It's weird, but sometimes I almost feel like I need a warm-up run for my recovery run.
Sometimes I think about the street I'm running on.  Right now many of the streets in Western Canada (particularly in northern cities like Saskatoon and Edmonton) still have dirt and sand on them.  It's not particularly attractive, but it keeps my mind active for a few seconds.  Sometimes I think about previous races.  The Saskatoon Police Half Marathon was my least pleasant because of the knee pain (which caused me to finish at 2:19).  The Chilly Half Marathon, despite being insanely cold (-17c), was actually the most fun.  The interminable walk from my hotel to the Pizza Hut was probably a bad idea after the Chilly Half Marathon.  I must have spent an hour walking on Guelph Line, freezing the entire time.
Saskatchewan is colder than Ontario, of course, but the chill of the cold in Ontario near the water is absolute.  
If I'm running in the cold (say, anything colder than -8c), then I'll probably reflect of my runs over the Williamsburg Bridge at least once.  Perhaps the thing I didn't like about the bridge was the rows of people I sometimes had to swerve around.  They always seemed to walk so slowly and devoid of purpose.  On the Manhattan side the bridge let out onto Delancey Street.  Sometimes I'd head east on Delancey, down a vaguely steep decline until reaching the foot bridge over the FDR Drive, and keep running along the East River Path.
I wonder if my mind would be able to function if I were to run in conditions colder than -20.  
Right now, thankfully, the temperature hovers between 2 and 10c, which is very good for running.

I'm not precisely sure what else I think about when I run.  Usually it's the events of the day or something along those lines.