Let ’er buck, y’all.A street scene in downtown Pendleton, Oregon.Credit: Heidi Besen/Adobe StockKey PointsPendleton blends its century-old rodeo tradition with underground history, Western shopping, woolen mills, and a growing calendar of events.Visitors can tour historic tunnels, shop for cowboy gear, dine at steakhouses and taverns, and experience the Pendleton Round-Up each September.Lodging ranges from boutique motels and historic inns to an…