Hey 160,
As it happens, we have the same PR in the marathon, but I was somewhat older (late 20s to your just out of college - I'm now in my early 40s), running higher mileage (mostly in the 70s and 80s to your 50s and 60s), and significantly slower at shorter distances (16:30s/27:30s to your 15:20/25:30). So, from my perspective, it looks like you have a good deal of untapped potential at the marathon, and with if you stick with it I wouldn't be at all surprised to see you run under 2:30 down the road. Whether you run 2:40 at New York this weekend is another question, not necessarily because of anything to do with your training so much as the fact that New York can be very challenging both tactically and logistically and is just not a great PR course in general. And the marathon is just unpredictable, so it's hard to say.
As far as your training goes in general, I think you're doing a number of things that I see as being positive. First, it looks like you were able to get in very consistent and consistently progressive training during a time when it sounds like you had a lot going on in your life. Second, it seems like you've been able to recognize the limits of your own time and energy and not overdo things (wish I were that smart...). Third, while I respect the perspectives of other posters, I personally think you were wise to put the emphasis on building and sustaining a higher volume (for you) while keeping the workouts relatively moderate. You're young and you have a strong speed background, so it seems to me like this was not a bad way to go not just for the sake of life balance but for long-term development in the marathon. If this was a significant step forward in terms of consistent volume, that in itself was the most important thing you could have done. In general, mileage plus moderate workouts with quality long runs is not a bad approach to the marathon.
As you're aware, though, if you want to keep improving your performance, you will need to keep improving your training. My own suggestion would be to keep that progression gradual: take the next logical step for you. (Emphasis on "for you.") So, this time you averaged something like low 60s for weeks 9-15, with a peak of 70. Maybe next time you might look to average mid 60s with a peak of 75. This time you did one workout a week. Maybe next time you might look to do something like one and a half (a full workout, perhaps building to something a little more demanding, plus a lighter complementary workout - probably something on the slightly quicker side). And similarly, the next logical step with the long run - probably the next most important factor next to overall volume (I don't remember what you said you were doing for the long runs).
One final thought: while the indoor track can be useful for shorter stuff, I would not recommend it for marathon-type workouts.
Hope this is helpful, and good luck this weekend!