[The_Ryujin]

Have you seen Spaceships 4? They have mecha rules and SM+4 hulls (smaller ones aren't that hard to extrapolate, things like propulsion, power plants, cargo, fuel tanks are always going to be proportional and weigh 1/20th of the hulls weight. Hull weight falls a 1-3 progression while HP and DR follow a 2/3rds progression and so on).

For GURPS Mecha, there are premade cockpits listed but if you want a more 4th ed version a cockpit would consist of either a computerized control station, holographic control station or if TL10 a multi sensory crew station (Ultra-Tech pg. 24), at lest a personal computer with harden and possibly high capacity (Ultra-Tech pg. 22&23) and some form of life support but that depends on how long the Mecha is supposed to be used (see Ultra-Tech armor design fromPyramid 3/96 Tech and Toys IV for more on life support options). I can help you out if you let me know your assumptions.

Now for ship DR, that's a whole hella lot of "it depends". Most modern warships aren't armored in like WWII ones were, even the Russia Kirov class large cruisers aren't armored (hence why the Russians don't consider it a battlecrusier like everyone else does). Their bulls at best are made of the higher end of mild steel (maybe DR56/in). If they are going to be armored then they should be able to stop the average damage of whatever is considered their main gun. Of course keep in mind that it is hard to armor ships in Spaceships since the TL9+ armor options are basically that TL's version of mild steel rather then military grade armor though that can be handled by just using armor that's 1TL higher.