For a 38 year old triathlete that is switching over to running for a while, is high mileage needed to run under 2:40 for a marathon? As a reference, I jumped in a half marathon a week after last triathlon in September and ran 1:17:00 pretty comfortably on around 30 miles per week, but always had trouble with the marathon. Looking at some plans for Boston marathon next year, and wondering what may be best. Pfitz? Hansons? Running 60-70mpw now to get ready for Philly Half this weekend, and tolerating that pretty well, shooting for 1:15:xx. Any suggestions would be appreciated.