Al,
A belated welcome to the BIAB forums. Some hot picking going on and it all sounds mighty fine. One suggestion: All of the lead work (fiddle, mandolin and guitar) seems to be on the right side of the stereo field. I would re-mix and move some of the instruments around. The stereo field is your friend -- use it.
Well done, for sure. I took a crack a bluegrass playing for awhile -- it was too hard and it took too much work (ha, ha -- my sig line makes sense in this context).