...You will run a better time at Boston next time if you train the same way, just by staying off your feet on Sunday but as your report shows, you already know that. You will run a better Boston next time if you train the same way simply because you know the course now. You won't be as nervous or make any tactical mistakes, and you may even get better weather, more like the cold of Ohio as you trained in. But if you think you will run a better time at Boston by cutting back on mileage and running more tempo runs, then you haven't learned a thing about the marathon. Spareribs...

I agree completely with Spareribs. A total revamp of your approach would be a mistake, imo, unless you just find it a drag to be training as much as you did. A couple minor adjustments, such as what you do the day before, could make all the difference. Maybe your day-to-day paces could be a factor, but I can't comment on them since you don't include paces on most days of your log. This often overlooked detail can be huge. In any case it is highly unlikely that this has all been for naught. You could easily have a string of PR's at distances other than marathon waiting for you as soon as you recover. This happens all the time even after things go wrong in marathon. It's exactly what happened to me after I bombed in my 2nd marathon. Run some other races and don't put all your eggs in the marathon basket...it's amazing how so much as a good 5k race can make you forget all about a tough day in the marathon. I see that you had very few prep races before Boston. Keep the faith!