Today's 7 mile run was at about 7:45/mile pace and that seems to be my cruising speed right now. I am comfortable there up to probably 12-14 miles, depending on when during the week I am running it. The weather today is back in the 20's and with a low, "feels like" temp. However, I was dressed right so no big deal.
Tomorrow's speedwork will be a workout designed to lower my cruising speed and to specifically get faster over the course of a race. I plan to warm up with a half mile run and then head into a 4-5 X 1mile repeat session with rest periods between each interval of around 2 minutes. I want to run the intervals between 6:15/mile and 6:30/mile. Then, finishing up, I will cool down with half a mile cool down.
Here is a good article about the benefits of mile repeats and an easy guide to the reasoning behind them: