Marathon plan advice

First marathon? Goal just to finish?

In that regard it looks adequate. I'm assuming 210 minutes gets you over 20 mile, though some may balk at a long run over three hours...

Just wondering why you would reinvent the wheel here rather than follow an established plan (e.g., higdon).

It appears to me that your Monday and Thursday (and later Saturday) runs for the duration are more like recovery sessions as they are relatively short.

I have a hard time figuring out what to suggest because while it seems to me that there would be adequate time/frequency on there to complete, the lack of specificity of each individual workout raises questions.  Obviously the Sunday runs are your long ones.  For those I would also not go over 3 hours as anything over that usually runs a higher risk to reward situation.  There is little adaptation over the 3 hour mark that would outweigh the risk of injury and the length of time for recovery.

And while there is a regular 3 week build/step back pattern, there is no real phasing in like "the first session is base, the second LT, third speed, fourth taper" as is the normal pattern for a build.  That would lend itself to more comments and a better peak.

I don't know if this is your first marathon or not, but if it's your first I would go past the 3 hour mark.  I think there is something to learn by getting up around 22 miles once before the race.  26.2 is a long way and 22 still leaves you the longest 4.2 miles you've ever run.  I do agree that when you go really long in training you need to pay attention to your body and leave yourself a month prior to the race to recover.

Good luck!