Probably the best start to this walk is the Bridalveil Fall car park. Walk a short way up the Wawona road towards the tunnel, then branch off left up the old Wawona road (used before they tunneled through Turtle Dome for the present road.) There is also a steep narrow trail up from the tunnel parking lot to join the old road if you prefer to park there. Follow the old road up on to Turtle Dome (there really is a magic about old abandonned roads - like Route 66 near Flagstaff), then sharp left and up the hill to Old Inspiration Point. From here the Pohono trail continues along the south rim of the Yosemite Valley past Stanford Point, Dewey Point, Taft Point, Profile Cliff, Sentinel Dome (worth taking time out to climb this (although the old tree photographed by Ansel Adams has gone now), and down to Glacier Point (refreshments here if needed.) from Glacier point, return to the Yosemite valley by Four-Mile trail, then follow the off-road trail back down the valley to Bridalveil. Maybe about 23 miles, all pretty easy and well-worn. But it's well worth it for the views over the Yosemite valley.