OK, started race off a little too fast. Wanted to break 5 hours, so wanted an 11:15 m/m pace to do 4:55. So, after first couple miles, which the excitement drove me to fast was able to dial in to my desired pace.
Then, to my surprise I saw DM'r Jim which was a great surprise.
Continued on at a good pace thru about 12-13 miles.
And then... aargh.... pain in my hip. Not enough to stop me, but enough to force me to change my stride. And, or course, the law of unintended consequences means that a changed stride will cause other issues. And yep, both calf muscles start screaming.
Now, I am resigned to some jog and some walk to try and avert a complete failure of the calf muscles.
Saw my Colonial Road Runner friends at mile 15 and mile 16 water stops. Most that I talked to realized that my stride was bad and things did not look good.
Checked into a Medical Tent to try and loosen the calf muscles, but essentially was told that I had two options - stop and rest (in which case my Marathon would be done) or to push on as best as I could. I chose to push on knowing the Med Tents were now at least every mile.
Probably the worst part (to this point) was the realization that as I got to mile 18, my reduced/struggle pace would mean 2+ more hours to push thru to complete.
Of course, I did what any sane person would do - push on. (HTFU)
Fellow CRR'r Pam saw my struggles on the hills and we talked. I assured her that I felt good enough to finish (wishful thinking!).
Finally into Boston. One point I remembered - put you name on your shirt - and the thousands who would call out my name, wish me well, give me high fives, etc..., really helped me slog thru those last miles. THe crowds in Boston are so supportive and great!
Finally, inside a mile. Very depressed knowing my earlier plans for a sub-5 were long lost, and a sub-6 did not appear reasonable.
Tried to push the jog more and more - big mistake!
By the time I took the right onto Hereford Street I was nearly in tears from the pain.
30 feet from the turn onto Boylston, my legs completely seized up into excruciating pain. As I collapsed to the street, a very nice couple offered to assist. But alas, no outside help. So I thanked them and said that as I crawled to the fencing and began slowly stretching the calf, that I would be all right.
By this point, I am fighting back tears as the crowds are screaming for me to complete the last few hundred yards.
Made my final turn on Boylston St., and even though the late hour, the crowds were still deep and yelling encouragement out to me. Limped my way to the finish, and collapsed again in pain.
Several medical people came out to help me, put me in a wheelchair, and someone began massaging my calf. After several minutes, I was finally cleared to either check-in to Medical Tent for IV's, or if I thought I could even slowly walk - to walk and gather my medal and belongings. They thought that if I felt up to walking, that it would be the better option.
So, gathered my medal and belongings, and changed some of my clothes. And guess what - blisters on both feet.
Anyway, not a DNF. Definitely not the race I planned for, but on the plus side: (a) finished, (b) had my nutrition and fluids in better control than last year, (c) was able to set a pace early and keep to it, (d) that I could push myself further than I reasonably thought possible as I experienced more and more physical issues.
Next up ... several days of rest.

Just got official results -
course time = 6:06:47
place = 23797 of 23962
male = 13749 of 13849
male 45-49 = 2547 of 2563