A waitress delivers our first course, a four-meat platter at Big Daddy's Ribs & BBQ. (Photo ©Chris Wilkins/Texas BBQ Posse) We called it our Denton County BBQ Tour, but it could have just as easily been named the Lake Country Tour. As we traveled 120 miles in 6 hours to eat at 4 joints on a recent Saturday, we crossed 3 different bridges over Lake Lewisville and drove atop the Ray Roberts Lake Dam. Seeing the water, the boats, the parks, and the nice shoreside homes was a pleasant respite from the heat, which approached 100 degrees. And then we…