When doing something like that, I screw a wide (1 x 6 or 8) board to the top and bottom edge of the door so that it overhangs both sides of the door equally. I put a washer between the board and the door edge to space it away so that you don't get puddles of finish building up between the board and the door face. This allows you to work on one side of the door and finish the two visible edges (hinge side and latch side) and then flip over to work on the other side of the door while the other side is drying. How much you can get done really depends on your environmental temperatures and airflow. The higher the temp and airflow, the faster things dry out to allow you to do the next coat. It also depends on the thickness of your coats and what stain/poly you are using. I usually allow for two days when finishing a door of any kind. One day for staining and a coat of polyurethane followed by a few more coats on the following day and allowing it to set up a good 12 hours before putting the hardware back on.
