Ok, I'll chime in here since I had a similiar experience to you in NYC a few years ago, some on the forum might even remember it.
I tried to break 3 hours in NYC and blew up with leg cramps starting around mile 16 (1:28/1:41)= 3:09
I woke up the next morning very disappointed and decided even though I was registered to run the Philly Half in 2 weeks that I was just going to do the full instead.
My new goal was just to qualify for Boston with a sub 3:05 and things were going fine running with the pace group until about mile 22 when I cramped up and shuffled home to a 3:08.
A few things- 1) You can't fully recover in 2 weeks from a marathon and it takes its toll late in the race. 2) It sounds like you were doing a bunch of miles at MP in between, I wouldn't have done that (maybe 3-4 on one run but that's it). 3) You are really playing with fire injury wise, hope this works out for you.
If I were you I'd go out VERY conservatively and try to negative split if you are feeling up to it. Also, its going to be very windy this weekend, if I were you I'd use this as a training run and try an assault on 3 hours at Rehobath Beach but that's me. I wish you all the best and hope you have a positive experience out there this weekend!!