I used to live right on the route and would wake up to the sound of the runners every Thanksgiving morning. I was just telling my husband the other day that its the one thing I will miss on Thanksgiving this year now that we've moved. For some reason, I always loved waking up in the morning and cheering the runners on in my PJs!
But I lived at least 2 miles from downtown Bethesda so if you are sticking to that area, you should be fine.