The Detours series celebrates lesser-known locales worth visiting across the state. One of the state’s most dramatic drives, the winding ribbon of two-lane blacktop in far West Texas known as FM 170 (or the River Road, as locals call it), follows the course of the Rio Grande as it meanders along the Texas-Mexico border. The mountains and canyons that form this rugged terrain provide miles of stunning vistas. But just below a dusty turnout on the river side of the route between Lajitas and Presidio (about 13 miles northwest of the former and 36 miles southeast of the latter) sits an unassuming roadside attraction: a boulder with “DOM” chiseled into it. Fans of Fandango, the 1985 cult-classic film about a group of five University of…