The hike up to Doc Holliday's grave is of moderate difficulty.  If you're used to higher elevations, you may find it easier and asthmatics ,may want to  bring an inhaler.  Not a bad walk.  Maybe 3/4 to a mile total and perhaps two to three hundred feet vertical.  If you're in decent shape, no problem.  Well worth the hike.  For a history buff, it's a must! 

Keep in mind that records were lost and no one really knows the exact location of Holliday's grave.  He's buried here, but the exact location of his grave is unknown.