Here's another thing I've been thinking of for a long time.
In TSLRCM, if my memory serves me well, right before you begin the HK Factory mission, HK-47 is seen in the Ebon Hawk, and in the next scene, he is in the factory.
But what happened in between those 2 scenes?
So here's my idea: What if you could navigate HK-47 through some modules until you reach the factory?
It's nighttime, and you have to make your way to the factory, fighting batallions of guard droids sent by HK units to patrol the areas close to the factory.
You begin in module 1 (It could be a module from the Dxun jungle, the second one, where you first meet the Mandalorian guards that take you to Mandalore).
You then proceed to module 2 (It could be the module from Malachor, the one that is basically a labyrinth).
Next, you go to module 3 (It could be another module from Dxun, or even Dantoine. Also, Quanon has created some awesome modules that he's giving away, and those include jungle modules too - http://www.lucasforums.com/showthread.php?t=206721
- although they're not ready to use, since modders will have to make some additional files to get them working in the game.)
And then you transport to module 4. This module should be the module where you crash and meet Bao-Dur for the first time. After that, you proceed to the next modules like when you had to in the begining of the game, when you travelled through a module with a beach with mercs and cannoks, then to RZ-0031 and finally in the old military base.
It would be just the same thing with HK-47, with 3 differences: First, it's nighttime (DON'T FORGET THAT!), second you're now fighting droids (TONS OF THEM!) and third, when you get in the military base, you will now be able to open the door to get in the HK factory.
That's all...for now.