>What major sections of the space hulk should there be
Nobody answered this part, but I think, that you can base it on the ship sections in RT rulebook.
>Enginarium
Gigantic maze of corridors, shafts, elevators and stairs growing like cancer around massive engines, generator and fusion plants. Leaking pipes, dripping fluids and whispering echoing through ventilation.
Loot rating: Rare
Loot volume: Small
Environmental dangers: High
Enemies are mainly: Rogue/corrupted servitors, mutants and small pocket of Heretek cults.
>Ship's storage
Vast halls filled with thousand of shells, containers or tanks with everything you will ever need, if you can find it hidden in layers of decay. Thread carefully, as there is always something lurking in shadows.
Loot rating: Common
Loot volume: Large
Environmental dangers: Low
Enemies are mainly: Mutants, degenerated crew/slaves.
>Gun deck
Long halls, filled with stale air and smell of death. Uncountable bays housing mightiest weapons forged on Mars, now left for decay, revered by those living here as holy totems of power their once wielded.
Loot rating: Uncommon
Loot volume: Normal
Environmental dangers: Normal
Enemies are mainly: Rogue/corrupted servitors, mutants and degenerated weapon crews.
>Bridge
Ivory towers and golden amphitheaters, nobility of those sailing waves of immaterium resides here. But beware of corruption hidden under flamboyant garbs.
Loot rating: Rare
Loot volume: Small
Environmental dangers: Low
Enemies are mainly: Degenerated crew/slaves, rogue/corrupted servitors, psykers.