MTH, I'm in nearly the same boat as you. My 40th is a few months away, and I'm gunning for 2:5X this spring.
Nice work with your mileage! I've been hitting mid-60 mile weeks for about five months ... hoping the snow and ice will recede enough to make 70 and 80 mile weeks palatable here. Sounds like you're in good position for an excellent spring marathon.
I really enjoy following this thread. Guess it takes a few years for most folks to learn how to play nice with others.