Horseshoe Canyon: Car regular won't make it
Some info for compat's who want to get to Horseshoe Canyon via the standard road (1010, Lower San Rafael). I tried it on April 6th with 07 Honda CRV. Most references I checked in advance indicated it could be done with a passenger car. Also checked with Hans Flat by phone and the Needles visitor center. Both indicated it could be done but that the road was heavily washboarded.
I made it in 5.7 miles before sand drifts stopped me cold. Gave it a shot anyway and spent a couple of hours digging out. Upshot here is that you must have a high clearance vehicle. Family type, or cross over SUVs will not make it. Your experience may be different as sand is a highly mobile surface. Just don't count on it with a standard vehicle.