As a professional carpenter, I have lots of tricks up my sleeve when working on projects. For example, before I dismantle a door opening, I examine the lay of the land—the door, whatever it shares a wall with, and any doors and windows nearby. That's because in old houses, one thing is often connected to another—this door was a good example of how projects can mushroom out of control if you don't think them through (and sometimes even if you do!).
My initial survey lets me work out an order of operation and set reasonable expectations for how complicated (and how messy) the job will be. All of this means that when you reach for your flat bar and hammer for the initial demo, you should also be ready with every other tool you in your arsenal, because you will probably need it. In the case of our door move, we had to deal with the following extras:
-Pantry shelves behind the basement door toe-nailed into the door's casing. This meant that all of the shelves (and everything on them) had to go.
-The cellar door abutted the adjacent hallway/living room opening, which meant we had to figure out how to trim both openings together in a way complementary to the house, while keeping them level with the trim inside the living room (the backside of the adjacent opening).
-Doorbell wiring running along the casing behind the basement door (needed electrical work).
-The hall floor—we knew we would replace it down the road. Knowing this, I chose to remove the 1970s linoleum beneath the jambs and replace it with header strips the same thickness as the new flooring (a task requiring my circular and reciprocating saws).