Brad from St Louis on 6/29/2007 7:33:28 PM:
I did that, plus more, back in September 2004. Including riding from and to my house in south St Louis and a little side trip to Columbia, I made the round trip in seven days. I camped out 3 days and stayed in motels 3 days. I was pretty tired the last couple days.
I think mid-september is a good time. I prefer cooler, but not cold, temps.
Good luck!