I live in an old DC rowhouse; it was built in 1908. I'd like to replace the house's two slab-hung exterior doors with newer pre-hung models with full-length lites to increase the natural light and to get rid of the gaps around the doors.
The problem is that I don't know how to go about installing a pre-hung door in walls as thick as ours. Instead of 2x4-framed walls, which would be a cake walk, we've got 13-inch thick walls, and that's before you get to the siding. On top of that, the front door has a transom window with only about a 1-inch plank between the top of the door and the bottom of the transom's glass.
How should I go about getting a pre-hung door installed here? Any tips?