I did three laps in Maryland Way park, and then I ran down Virginia Way to Granny White and back. I ran into headwinds about 25% of the time, and of course there are some hills to deal with.
I ran the whole time (no walk breaks), and I focused on running right at the level where I could always catch my breath. By the end my legs were tired, but my breathing and heart rate were still fine. My calves are still sore from Sunday and Tuesday. :-(