M. Newbie - echo the sentiments on the rain - I have only had to ride in the rain twice in the past month.
re: the MT Vernon Trail - it is much worse on the weekends, full of tourists, uncontrolled kids and side-by-side strollers - I try to stay off it then. During commute hours (esp) morning, there is a lot less traffic and those on the trail are regulars - some are so regular that I can tell how late I am by where I pass them. that is until you hit gravelly point up by the airport - that is always a mess.
Not commuting again this week (still home with the kids while my wife travels) but I have been able to get in a couple of good rides.