lagary has your answers. Be aware that the vip211z (single tuner) and Tailgater (single LNB) can only "see" one satellite at a time. So even if you connect to multiple TVs, those TVs cannot watch different programs that are on different satellites at the same time. They would be limited to programs on the same satellite. There are other receivers and satellite antennas options available for multiple TVs.
Another problem often encountered with satellite is in the internal coax wiring of the RV, many times inferior or poorly installed. Some have resorted to adding a new coax input from the outside directly to the satellite receiver inside to bypass that internal coax wiring.
As far as Dish customer service, even their RV specialist have no way of knowing how every RV is wired and the multitude of ways to get around that.