The marathon training program I'm using includes 5 runs of 18-22 miles. I'm doing the first of these tomorrow when I'm up in Connecticut. I'm shooting for 18, which will be 2 miles farther than I've ever run.
I've been tired and achy this week. I'm not sure why but suspect it has to do with lots of mileage in the heat and humidity. Though I've been dreading tomorrow's run for most of this week, now that I've figured out my route I'm starting to get a bit psyched for it.
Wish me luck!