There's a fair bit of SNOT work that's hidden, which is probably way more complex than it needs to be for the overall shape, but I wanted to be able to tile the underside to hide the bottom of the plates, so that the only holes visible would appear to be thrusters.
Roof off, showing inside the cab.
Took a real effort with this model to reorganize the mlcad file in a way that the instructions would be usable, so please download it and take a look. The roof and the tops and bottoms of the engines would need to be build separately, but that's the only place where any pieces float in the instruction steps.
Edit: fixed a couple illegal moves that slipped by me in the instructions.