The manual makes the following distinction:
Yellow (ignition) through a 5-6 amp fuse to the fuse block.
Red (Power) through a 20-25 amp fuse/circuit breaker, through a battery disconnect, to the battery.
The diagram doesn't say the battery is the house or chassis battery, but by showing the disconnect, it implies the main power is from the house battery. Yet, there could be a disconnect on the chassis battery as well, so it could be either battery.
(I would presume a disconnect would be on the house, however.)
Regarding the magnetic door switch: (Edited, had N/C, N/O backwards)
If the switch is white, it is a N/C, Open when the magnet is in proximity.
If the switch is black, it is N/O (normally open), therefore Closed when the magnet is in proximity.
(Edit) All steps from 2/99 use the black N/O magnetic switch.