[Disgruntled Goat]

Hey eas

As far as the MG-42, in the entity window (press n when mg-42 is highlighted) use this
key: maxyawoffset
value: 70
This means it will swing 70 degrees from its axis.
As far as walkthrough models, build clip brushes around them. In the texture category 'common' there is a texture called clip. Make brushes inside your vehicle with this texture. Players can't see it ingame and it will stop them from walking inside models.