Thought I would give an update on our project. We have our new inside door up. My husband put it up, and it works great! We got hardware and everything, and it works so good. Still need to cover the floor in the area of the no-more step, but that is minor. It was not the easiest project to hang a door there, because none of the corners were square, so the door isn't either! And, can't put on a sash because of the unevenness of the floor - 2 inches difference from one wall to the steps! We have a true THIS OLD HOUSE! Thank you for all of the help!
Glad it worked out for you and thanks for the follow-up.