Moving level inside landscape


i’m working on a game where i need a big level with several rooms moving, driven by physics, through a terrain/landscape. The moving level is a ship / spacecraft like thing with windows to the outside and several stations inside.
Making the ship dynamic seems problematic concerning performance and inner physics. The players are moving in first person inside the ship.
Making the ship static and projecting the landscape on a sphere around it isn’t the best solution is suppose (performance and interactions with the surrounding?).

Does anyone have an idea how to solve this? Another questions is, can i anchor the player characters to the ship somehow so they move relative? Right now the whole ship is dynamic, what seems to work, but the characters begin to stutter at bigger speeds (physics problem i think). I need this to be network compatible, too.

Thanks in advance!