I personally think that 50+ miles, and running over 5 days is really not necessary if you want to run sub 3.30. I can understand higher mileage for a sub 3 hr, and it is probably necessary for the over 40's.
No Cougie, the 60 miles is out of necessity, with the wife having the car for her job. The reason why i chose a less runs approach was really because i had been suffering with osteoarthritis in my left toe and needed more recovery time. I do not think i have much natural ability! I have done a fair bit of track cycling, the odd duathlon, bike time-trials etc. But i am distinctly average.