Dreamer,
The coax from the roof mounted dish comes into the front "entertainment equipment cabinet" over the windshield on your coach -- just to the left of the front TV. To my knowledge, it does not go anywhere else in the coach. The below image is representative of how these GS units are wired. Your unit uses the more capable AV5200HD Audio/Video box instead of the composite video AVS100, but the architecture is similar.
You would need to have an additional coax run from the current satellite dish to a bedroom receiver if you want two receivers, but may only need to EXTEND the coax to the bedroom area if you are only using one receiver at that location. Remember that the coax must be high quality and capable of 1.5 gigahertz bandwidth, so even if you were inclined to 'remap' the coax from the distribution box to the off-air/cable run to the bedroom TV, that particular piece of coax may not be of the right quality to support the higher frequencies needed to communicate between the dish on the roof and the DirecTV receiver equipment.
Further, if you locate the sat receiver at a location other than near the A/V distribution box, you cannot route the satellite content to all the other TV sets in your coach...
Chuck