What I did in the Hellthrasher was to have a main engine for propulsion, and a secondary small engine (<2L) for power generation only. If I needed more battery then when I stopped for the night I would turn the main engine off, switch in the little engine and run it overnight. A small engine (1 fuel consumption) with a truck alternator running while you sleep can produce a lot of battery power by morning.
A square counts as ‘indoors’ if it has a roof and all 8 of the surrounding squares have at least one of
- roof
- door
- quarterpanel
- board
So if you want to enclose the whole vehicle then you should put a roof or heavy duty roof on every square that isn’t a door/quarterpanel/board. It’s only really necessary to have your driving and sleeping stations count as ‘inside’ though, and that only for comfort. A roof only needs sheet metal, which is easy to mass produce.
(You can see if a square counts as ‘inside’ or ‘outside’ when examining it in the vehicle viewer)
The most important part of enclosing your truck though is to replace the (transparent) quarterpanels with (opaque) boards, and then put in an opaque divider between the back and the driver’s seat (use an opaque door). When you stand in your sleeping/crafting area you should not be able to see out at all, because if you can then things can see in and will interrupt you all the time.
What I did with the Argo was to put shutter doors all around the driving area. That way I can open them for driving and have a good field of view, but shut them at night and be completely concealed. The Hellthrasher used a divider between the living area and driving area which works fine, but takes up space.
