There is a 16 week marathon plan on this site which has three runs a week. One tempo, one hilly or speed, and one long run. I used this to train for my first marathon, having previously only run 10k's. What I didn't do was run the long runs as 'slow'. There were only two 15 milers and two 20 milers, so I didn't feel I had the luxury of running them 'slow'. I wanted to get an idea of what pace I could maintain for the marathon, so ran at what I thought was my marathon pace to achieve a 4hr marathon. Now I may just have been lucky, and could have been over training, but I maintained that pace for 20 miles on the day, then slowed for the remaining distance, finishing in 4:17. So to me that is a good argument that quality wins over quantity as I didn't clock up a huge mileage in training.
My first marathon experience based on a 16week plan, 3 runs a week made up of 1 tempo, 1 speed/hills, and 1 long run a week. I maintained a 4hr pace for 20 miles, then dropped off dramatically in the last 6 miles. My finish time was 4:17. In reality I missed 3 weeks of the 16 due to illness and injury, so I don't think thats too bad.
Whilst marathon training I suffered from shin splints due to increasing mileage too quickly. I took a week off, then decided I was going to be proactive. I researched possible treatments, and came up with the following...
2 days of no running but intense stretching which involved being seated legs outstretched and pulling toes up towards body for 5 minutes at a time (that doesn't mean pulling them with your hand, difficult to describe without pictures, try Youtube search for shin splint stretches)
When i did run after a week of rest I did about 2 to 3 miles, further stretches focussing on the front and rear muscles of the lower leg (again youtube search for stretches)
This worked for me, but highlighted the need to stick to a training plan and not panic! Your body is very good at telling you when something is wrong, listen to it, never use the ibruprofen before running, only to ease the inflamation afterwards. If it gets too much while running, STOP!