Nail three pieces of 1 1 boards into the cased opening on the opposite side of the door swing to hide your gaps and keep the door from swinging too far inside the frame.
Add a door to a room.
It s not quite wide enough to frame in one side and make a pocket door but i would think if you trimmed the doorway it might work to use two 24 inch french doors.
4 measure the width of the interior pre hung door and add 3 inches to the measurement.
Remove the plaster or drywall to this point and cut a straight line across the studs you want to save.
When you are seeking a quiet study the extra door will allow you to keep the existing door closed and reduce the noise and commotion in the room.
Unless you want to add a bit of de and re construction to this project the barn door type would be the only sliding option i can think of.
To preserve the cripple studs calculate where to cut them by adding the jamb height included in the packaging for pre hung doors and the header size calculated below plus inch wiggle room.
I used this oil rubbed bronze privacy lever door handle.