Ahhhh I don't have the 3400 but......
Gen prep in the 3670RL starts at the shore power connector. The cable runs through the underbelly and through a hole into the front compartment. It passes through a Magnatek switchover relay, then goes back through the underbelly and come up into the power panel.
Nothing in the walls, nothing in the ceiling.
The remote start switch is fished up under the bedroom floor and is installed in the cloths closet wall. I guess in the 3400 you could install it in the kitchen.
The generator sits on a metal frame, about 6 inches above the compartment floor. The floor has index marks which allow a 12 x 12 (more or less) hole to be cut to let hot air out.
A carbon monoxide detector is also included in the living spaces.
Hope this helps.