Frio River, Texas Popular summer recreation area offering tubing, canoeing, kayaking, etc. River parallels US 83 and runs through Garner State Park Campground. Ranch Road 337 (Camp Wood to Medina) Ranch Road 337 RR337 between Vanderpool and Leakey in an area known as the \"Swiss Alps of Texas\". The rugged terrain and elevations as high as 2100 feet above sea level makes this area popular with recreational motorcyclists and bicyclists as well as those who enjoy sightseeing. With tall, dense, mature stands of Ashe juniper mixed with Texas Oaks and Lacey Oaks along the steep-sided canyons, this stretch of RR337 has been designated as one of the most popular scenic highways in Texas.