I only did the trail between St. Charles and Defiance/Augusta/Marthasville. Plus a small stretch around Columbia. 5+ years ago.

There was often wind out in the flats near Augusta/Marthasville, but I can't remember which direction.

The trail is fine crushed limestone, and when I did it, reasonably well groomed.

I always rode it on my old Colnago Super with 23mm tires, I think. I could definitely feel the extra rolling resistance attributed to the gravel, but never felt that I wanted any other bicycle for it.

If you are into wine, there are a number of wineries along the trail (which should be accessible by both road and bike).