I ran the same run last night as I did on Tuesday: 4.5 miles, almost all grass trails/fields. This time, I averaged 8:37/mile compared to 8:15 per mile on Tuesday. I think the effort was similar, although I only did one fartlek during this run. It could be that the Tuesday run followed a day off on Monday, so the legs were fresher.
Anyway, I'm up to about 13.5 miles in 3 runs so far this week, with two more runs planned.
Next week, I'm out of town all week again at my brother's house (working from there), but I hope to get in at least 4 runs next week.