Steve, are the distances you posted (i.e. 102 miles for Buena Vista in TX) straight line distances? That could definitely explain the difference. And what is it 102 miles from?
I plugged the two sets of coordinates into this GPS Latitude and Longitude Distance Calculator, and it spit out ≃113 miles
http://www.dgcoursereview.com/course.php?id=3511
~102 miles with that link