adding a portable antenna

I have a Winegard Travlr SWM antenna system mounted on the roof of my RV.  It serves 3 TVs, allowing independent operation and watching.  We are currently stationary at a seasonal site, and the roof-mounted antenna is hopelessly blocked by trees.  I have a location nearby where a portable dish would have a clear view of the satellites.  What are the possibilities for disconnecting the roof-mounted antenna coax and swapping it for a new portable dish?  The easiest solution would be disconnect one of the connections on the roof, on the exterior of the winegard unit, as I wouldn't have to find a way to route the cable into the interior of the RV.  Is this a possibility? Are there other options to consider?  I'm assuming that I need to replace the input to the SWM unit with the new coax?  Thanks in advance