My '99 T-2453 is the same, amplifier plate at one end, and just the cable at the other end of the trailer.
My guess is that the cable is there to make it easy to install the TV in the cabinet where the cable is.
In the bedroom, where the switch and connector plate is, the TV would go on a flip up TV shelf on the wall. We took that flip-up shelf and moved it to the kitchen and picked up some nice counter space next to the stove.
'12 F250 4x4 Super Duty PowerStroke 6.7 diesel
2011 to present: '11 Cougar 326MKS
1999 to 2011: '99 Sunline T-2453
Amateur Radio kd2iat monitoring 146.52