Fords Theater is still open today, and producing plays, although I believe it is owned by the Park Service. In the recent past, when the president wanted to attend, the Secret Service would go over the top with his protection, including using a steel type of collapsible tunnel from the curb to the entrance for safety. They did not want the same thing to happen twice at the same place.
Ford's Theatre was eventually turned into government offices. In July 1893 the whole inside of the building collapsed. 22 people died. What we see today is all rebuilt and not original.
The Collapse of Ford's Theatre
Many years ago, an historian acquaintance who lived, and worked in the D.C. area took me to Ford's Theatre. I'd been there years before with my kids. He knew the head Ranger in charge of the site, and the Ranger took us around the theatre, and allowed us to access the President's box. I have no clue if the box was spared in the collapse, so what I saw that day may only be the reproduction created when the building was put back together.