Ship and mission resources are the two hardest. Let me try to explain, a ship resource is only one part of it. Here's what goes into making a ship:
1. The ship resource, as you know, gives stats, what the AI is to do with the ship, etc.
2. The shan resource, which gives, among other things, the....
3. RleD and rle8 resources. The rleD resource shows what the ship looks like flying, the rle8 resource is the base, the outline, the shading.
4. The desc, as mentioned above, describes the ship. It also describes it in the hire escort at the bar. The desc resource used is predetermined and can be found in the lower-right hand corner.
5. The pict resource, which shows what you see in the shipyard, as well as what you see when targeting the ship in space.
I believe that's it. The desc and ship resources are probably the easiest, the pict and rleD/rle8 are only hard if you're graphically challenged (like me), and in my estimation, graphic issues aside, the shan resource is hardest. I generally try to leave sleeping dogs lie, there.
Hope this helps.