Details on the internal floors. Lots of fun widgets and mechanisms purchased from a mate of mine who does laser cutting @ miniaturescenery.com
The door details were really fun to try and find pieces that would form a mechanism to close and open the doors.
I have filled the bottom up with expanding foam so give the impression of wind swept sands into the cavity below the crashed ship.
I've been told that Range https://www.therange.co.uk/
in the UK has the foamboard as well as Hobbycraft.