The Texas BBQ Posse returns to Snow's BBQ in Lexington. (L-R) Mark Vamos, Jim Rossman, Bruce Tomaso, Chris Wilkins, Michael Ainsworth, Gary Jacobson, Daniel Goncalves & Tom Fox. (Photo ©Tom Fox) We weren't on the turnpike from Stockbridge to Boston. And it wasn't snowing. Still, James Taylor would have liked the scene. In the early morning sun, a white frosting covered the fields along the highway from Austin to Lexington, Texas. Ice crystals glistened, almost as if they made their own light. It was a nice way to begin a barbecue tour, especially since we were headed to Snow's BBQ,…