The countdown has begun for thousands of runners who will head to Myrtle Beach, South Carolina, for the annual Myrtle Beach Mini Marathon, Coastal 5k and Doggie Dash on Saturday and Sunday, October 19 and 20, 2019. This annual half marathon is a favorite among runners due to its flat course, mild temperatures and scenic coastal backdrop. The marathon weekend offers three separate events for runners at all skill levels: The Coastal 5k, Doggie Dash, and the Myrtle Beach Mini Marathon. The Coastal 5K event (3.1 miles) is set for 6 to 11 a.m. on…