A statement to myself, as I contemplate what they hell I'm going to do this fall: Don't try 100 miles.
You're not ready. Not mentally. Not physically.
In your best 50 mile performance, you averaged about a 9:30 mile. Not aerobically taxing in the slightest. Why? Because your legs couldn't handle really running the distance. So you jogged it. Which was smart. On that day, that was the best you could do.
Sure, you remember the last few miles. Finishing felt good. Winning felt better. But it hurt, didn't it? And those middle miles? 32-42? When you swore off, for the third time, ever doing anything this goddamn long again? Remember that?
I'm not saying to avoid pain, or that you don't have the capacity to endure it. What I am saying is that the damage was severe, even at such a slow pace. Your legs were telling you something crucial, something you shouldn't ignore. That your limiting factor is your training age, and thus your lack of structural and slow twitch development.
Sure, you've run consistently high volume for two years. Put another way, though, you've only done that for two years. No single training cycle can make up for that. No several training cycles can.
If you try 100, it won't go well. Not by your standards, anyway. You want to run it, for the most part. Approach it basically like any other race. And that won't work. Maybe not ever, but certainly not now.
Simply, you can't rush these things. Don't try.