Pretty much that's it in a nutshell. You might want to drop some thin CA down the hole before you install the transmission to harden the wood. Give it a "re-drill" after it dries. This will help harden the wood at the nib.
I have something up my sleeve right now, but without giving it away I have a plan much like this. I plan to use the method of tapping the blank (closed end style) onto the end of the pen mandrel. I want to drill the center line for the refill before turning while leaving the blank longer than needed. This hole will center not only the blank in the live center, but once it is drilled and held centered, you can shape down your nib and part it off. If your measurements are good, you should be able to do all the internal drilling before turning. The needed hole to thread the mandrel onto will be wide enough to allow the refill to fit thru. I have not decided if a second smaller hole will be needed before the refill hole, but that should give you a couple ideas.