South from Blanding to SR-95, continue south until you reach county road 263 (Arch Canyon). Turn right onto 263, go about a 1/4 mile, then park on the pullouts you'll see. Go down the hill on the left side of 263 and you'll be on the trail. Follow the trail about 1 1/4 miles and the ruins will be on your right (about 20 feet above you) as you round a bend.
The spectacular colors appear only for 30 minutes or so each day. The sun has to be in the correct spot so that its rays reflect off of the red floor and up onto the sandstone "ceiling". We went in July and the time was from approximately 1 - 1:30 p.m.