Russo: You really should try and adopt the habit of mapping and texturing your model BEFORE you start cutting hatches and doors into it ;)
On the new AFX model, I actually began by taking what drawings I had and mapping them out on a texturemap with all parts before I even started modelling the plane in order to create a "shopping list" of sorts for the actual modelling. I also included random parts of machinery (weapon bay and doors from an F-22, some gear well interiors from an F-14 and an F-18 and miscellaneous other parts) that function as a palette of sorts for when I model. With this method, I never have to worry about how to unwrap what part and how to paint it because I already have a texture that looks convincing enough and similar areas can easily share the same piece of texture or even tile around (for edges of doors and such) and I can literally texture as I model.