Ancho Canyon Trail actually connects to the river trail at an obscure cairn about 1000 ft back from the Rio grande.  Ascend on the clear trail you see going up a low hill and find good trail for the next 1/3 mile until you come to a large branch pile in the small Arroyo you are following.  Make a sharp right here and follow the white dots for 2 miles to water canyon where a nice beach for lunch is found.  Continuing on you pass the beautiful Pajarito springs, a field of amazing petroglyphs, and then proceed up the blue dot trail to the White Rock overlook.  Two cars are needed to close this loop, with 7 mi of road between the two trailheads.  This is the finest loop in White Rock canyon, and only requires 1,400 ft of elevation gain and 9 miles.