The Tailgater system will allow you to watch one channel. You can see it in HD in the living room (receiver connected to your TV with an HDMI cable) and you will be able to set it up to watch that same channel in Standard Definition on the other TV(s). If you are good with those limitations, then yes, the CW Tailgater package is great. If cost is an issue, you could go cheaper by buying a tripod and dish and aligning it yourself (instead of an automated system).
If you don't have Dish at home, you can use their pay-as-you-go option. No contract and you can pay only for the days you are out camping, which can make it really cheap.
According to the specs on your RV, you have only a single exterior connection for a Cable or Satellite input. (There is prep for a roof-mounted sat system, but that won't help.)
What this means is that on the inside of your RV at the Antenna Booster control plate, you have to disconnect that Cable Input from the booster plate and wire it directly to your Sat receiver.
Here are a couple of pictures.
(In the second picture, the connection from the output of the receiver is how you would get that SD channel into the other TVs.)
Here his one persons suggestion on how to make it where you can change from a Sat configuration to a Cable configuration easily: http://www.forestriverforums.com/for...?do=file&id=97
(In some new RVs they do this jumper setup on a separate wallplate.)
This should get you off to a good start.