Norm,
I am not sure if you mean the Winegard Carry Out at around $400. The Traveler is nearer $1100 and is a rooftop system. I have a Carry Out which I use on both my roof and the ground with a custom mount system. The antenna itself works very well and is simple to set up. It toggles between satellites quick enough where it is hard to know if it is even toggling with a channel change. I think it works best with a single tuner set up feeding the whole coach but I use two tuners with a 722 Dish receiver with some added limitations. Separate channels being watched have to be on the same satellite to be viewed. Because the 722 was not set up for that situation you will get screen error messages about lost signal on the alternate TV if you try to choose one that cannot be viewed at that time. There is something new called a Pathway X2 also which may fit the bill.
I would be surprised if you could use the feed from the water bay. If it passes through any couplers or if the cable is RG59 instead of RG6U it probably will not work. You may be in better shape cabling wise with your newer coach than I was. I had to run a new feed. Lastly the Traveler for about $1100 is probably one of the best options out there. Strong signal, watch all channels anytime on multiple receivers, absolutely no set up and stowing to do. If you could not get ready access to run cabling from the bay to the satellite receiver location that worked, you may find it better to go to the roof side of things and have a Traveler added.
Later Ed