A new twist in the cramping mystery? (They started early, caused walking and jogging, then resolved in time to allow me to run a decent 1+ miles to the finish.)
I now recall taking my 3rd (of 3 total) S-Caps (salt capsule) somewhere on Summit Ave while talking to another runner who was walking. (I took 2 S-Caps shortly before the start.) Maybe at mile 23 or 24? Could it have been the sodium in that 3rd capsule that kicked in by about mile 25 which caused the cramps to subside for the last 1.2 miles? I just read an article about a "heavy sweater" that resolved his cramping issues with sodium -- "consuming around 1,000 to 1,500mg of sodium per hour during long races." I'm not convinced that this alone will cure me, but it wouldn't hurt to experiment more with it. These S-Caps have 341 mg Sodium per capsule, so I'd need to take 3 of these per hour to get to ~1000 mg/hour. That is a LOT more than I have taken in the past, so it's worth a shot. (The Endurolyte capsules give me an upset tummy, so I will give up on those.)
Other things I could do better with respect to training:
I did very few FFLR's this cycle. Also, no long O&B's at near-MP for 15-17 miles, as in the old RW plans. I relied primarily on the Alternations workouts, but my longest was only 11 miles. My Long Runs didn't have much in terms of "fast" stuff during this cycle.
I also didn't stick with the SAM routines. Plyometrics is something else to mix in -- hopping, skipping, etc.
Lastly, Stretching. A lot of it.
MTA part 2:
My 23 mile training run was just 3 weeks before the marathon. Maybe that's bad all by itself. But the PACE of that run was an average of 7:37, almost as fast as my average pace on race day. And my pace on the 23-miler for the last 13 miles was probably under 7:20. Sooo, it was probably BOTH: a) too far, too close to the race, AND b) too fast. My HR during the 23 was lower than for the race as well, and not even close to cramping.
MTA part 3 (edited on 1/6/2022):
The week before the 23-miler (4 weeks out from TCM), I ran City of Lakes Half marathon in 1:27:37 (6:42 avg pace), close to a PR in the Half. That Half Marathon 4 weeks out, followed by a super tough 23-miler 3 weeks out, ... well that is just so stupid to look at in hindsight. I still think this was probably one of my best chances to go under 3 hours had I managed these 2 runs better, or skipped one of them ... or possibly both of them. Oh well.
Another workout that sounds appealing (as part of the FFLRs and Long O&Bs mentioned above) is a 5-4-3-2-1 workout, where it's a total of around 20 miles, where you w/u for 1 mile, and run 1 mile c/d between the MP portions. This yields 15 miles at MP spread out over a 20-miler.
It's frustrating to think that so much went well this cycle ... yet I may have screwed up with just a couple of things that de-railed my race. Seriously, I would have run a faster full marathon on the day I ran my 23-miler if I had just continued another 3.2 miles.