Yep, been doing it for years. My last attempt at a BQ in 2009 I averaged 70 MPW for 8 months. Over 16000 miles in the last eight years. I started slow, built up to it over a few training cycles. I don't believe in junk miles. I think you get better by running more. The problem is running to fast and increasing mileage to quickly. I have never gotten hurt running easy miles. I have gotten hurt running speed work and not running easy when my body was telling me to.
Here is a great set of basic traing principles by Jack Daniels.
http://www.coacheseducation.com/endur/jack-daniels-june-00.htm
If you are planning on running the marathon I think you would be better served slowly increasing mileage and cut out the speed work except for strides to improve running economy. We probably disagree but I am ok with that

. It's not for everyone but I LIKE running everyday. If I need a rest day I will take one. I just don't have it on the schedule.