An 18 week schedule for Rocket City would begin today. I still feel like I need to do some more base building before I venture into a steady diet of tempo runs, mid-week 15 milers, and marathon pace long runs. So for now, I'm still doing mostly easy runs and building my mileage back up. I'll re-assess my fitness and general feeling in a couple more weeks and may go with a 16 week schedule.
Another option is a 12 week schedule. That's what I did for Nashville, and it worked out very well. However, I rolled into that 12 week schedule with a very big, solid base. I'm not sure that 12 weeks will get me to a PR in December.
The 10 miler was hot and humid, but fun today.