First of let me tell you I too have two TV in my house. One is on the ground floor and another one is in the first floor and similarly like you I use only one TV at a time. So if you are good with TV cables you can hook it up in such a way that you will get it on both the TV’s.
Here is what I did, there are two outputs on dishtv set top box. So the audio video one goes to my TV and the other output goes to my TV up stairs. And when I switch off the down stairs TV I just leave the set top box switched on and I get dish TV in the room upstairs.
But there is one problem since the box is downstairs you cannot change the channels so what you do is set alerts to the programs you want to watch and go upstairs. when the program time comes it automatically switches to the channels you set the alerts for. This is a free and easy work around the problem.