Some 2x4( 4x4 for extra piece of mind) or 6's rigged to the door way and stepped out 3 or more feet, Like an A frame on each side of the door and then a cross piece at the apex of the a frames ( gantry on its side) I use come-a-longs hooked to appliance dolly or skid or unit depending on configuration and the other end to gantry very controllable due to the come-a-long ratchet system. Just have to make sure there is enough length on the come-a-long. Sometimes I use 2 of them in series to get where i need to go. Reason we step out aways from the door is to avoid riding the cable on the threshold and we place higher up the door way so we have a straight shot. Stairs that wind are always a challenge.