After going through the thread I thought I'd give a little more color. Keep in mind, this was just how I personally implemented it, and obviously everyone is different so I'm not saying this is the only way to do it.
I've always been very anal about running this the way that was indicated in "Joe's" training. What that meant to me is 2 times a week I ran for an hour at 160. Not working my way up to 160, but at 160 and no more. So a week for me looked like:
M: an hour at 160 (usually with a mile warm up and cool down). I'd hit 160 in the first mile and then stick there. I ALWAYS slowed as the run went on.
T: A recovery run under 140
W: A medium long run at 145max. When I started this would be 40 minutes, as I got more experienced this got upwards of 15 miles
TH: Same as Monday
F: Same as Tuesday
S: Long run, 145 max, upwards of 22 miles as I got more experienced but when I started it was definitely shorter. When I first started Hadd the first time I let this go to 150 the 2nd half of the run and slowly eliminated that.
S: A recovery run under 140
I never ran by mileage, except for maybe the long run, I always just ran by time. And once I got to where I felt comfortable I added doubles. In 2004 the highest mileage I got in a week was 75. But by 2007 I used this structure to hit 125 (which was too high for me, I learned).
My advice, do whatever you have to do to be able to hit the 160 ones for an hour. Prioritize those 2 each week as Hadd says (they are the work days). Then prioritize a weekly long run. Then once you're good with that, add the 145 day midweek. And then worry about