Ooh rah! Congrats on getting in. I'm not running, but I live outside DC, so we may go cheer.
DH ran with a Coast Guard team in Nov. 2001 - it was quite a year to run that race. What stuck in his mind was that every time he went under an overpass, there were people on the overpass waving flags and chanting "U-S-A U-S-A." It has become a thing in our family, now we all chant U-S-A whenever we run under a bridge!
I am running MCM with Charlie (Judy's -- aka Honeibee's DH).
This will be two MCM's in a row for me. My marathon PR is MCM 2008 (4:10:39). It is a challenging course to say the least. Best of luck training and please do some hill work too. My goal is to break 4 hours this year. A lofty goal given the course and challenges it offers to all.