Calibration was done using the projector corner mode keystone adjustments, and adjustments on the mirror mount.  This projector has a corner mode keystone adjustment, which instead of the typically keystone, just lets you shift each corner, in either axis, arbitrarily.  As I made the whole system orthogonal, actual keystone distortion was not present, but this feature was used to shrink the image horizontally about 2%, to match up 1 to 1 in both axis.

The mirror required slight adjustments to the suspension cords to correct for a very slight twist that was being imparted on the mirror by uneven tension in the cords.  This was visible in the projection as a very minor shrinking of the image along a 45 degree angle.  Slightly tightening one of the cords pulled the mirror flat again.  The  below picture was taken prior to this adjustment, which is why it isn't perfect.

This calibration was done using the calibration pdf in the Projectors For Sewing group, along with a cutting mat.  The cutting mat as well as the table are slightly bowed creating some unevenness, but overall it is extremely accurate.  Across the entire 48" width of the projection, a projected line does not deviate from a straight edge by more than 1/16", which is mostly due to the bow in the table.  Vertical and horizontal lines are perpendicular to within less than 0.5 degree(within the tolerance of reference grid)

I ran a long IEC power and VGA video cable to the wall, held up by a hook to keep it out of the way.  

The mirror can be simply folded up and latched flat against the ceiling to keep it out of the way.

The mirror and projector are on simple hooks so they can be taken down quickly if needed.