Hi I currently have a base of 14 miles for my long run and recently did a 1/2 marathon in 1:37. I run 4x a week 20-25 miles per week I still have 19 weeks until mk marathon and I'm going to follow the intermediate plan in the latest rw mag. But I have read that you should do 4 or 5 long runs 20+ miles. Should I just tweak the long run distances on the plan? I'm training for a 3:25 marathon so in theory my longest run should last for 4 hours? I struggled in the last 4 miles of my previous 2 marathons!!