Libby & Gunnar Jacobson at the cabin on Grindstone Island in 1991. (Editor's note: Making a nod to Thanksgiving tradition, we're re-running this post, first published in 2013.) With the Posse, I've eaten turkey at some of the best barbecue joints in Texas, including Franklin Barbecue in Austin and Stanley's in Tyler. Their turkey breast is first rate, no question, just like their other smoked meats. But the most memorable turkey I've ever eaten still remains Walt Scheela's, cooked at his cabin on Grindstone Island. The ambiance is important. One of 1,600 islands in Rainey Lake, Grindstone is located about…