Ok. Good. Let me say right up front that you can't do a DVR and another receiver. You can do one DVR *or* two non-DVR receivers. (Eg, a max of two tuners.)
First you need to find the Satellite connection inside your RV. It might be on the Antenna Booster Control plate like this:
or by itself somewhere. Connect one of the dish LNB ports to the outside Sat connection and one receiver to that port on the inside. (One down...one to go.)
For the second receiver, you have to do what folks do when they have only a single coax input for both, which is to remove the "Cable" wire from the back of the Antenna Booster Control Plate and connect it to the second receiver. Here's a picture if the back of that plate.
Remove the "Cable In" wire. Note also the "Set 2 Output" wire.
If you are fortunate to have the Sat port (for the first receiver) at a different TV location than the Antenna Booster Control plate, then just connect the "Cable In" wire to the back of the second receiver and you're finished.
You're probably not going to be that lucky. This means that you have to use the over-the-air antenna coax wire that runs from the antenna booster plate to the other TV location to continue the "Cable In" wire to its destination in the other room. If you only have two TV outlets in you RV, then the "Set 2" wire will run directly to the other TV. If you have more than 2 TV outlets, then there will be a splitter connected to the "Set 2" port and one of the wires that is on the output of that splitter will go to the second receiver location.
Use a "barrel" to connect the "Cable In" wire to either the "Set 2 Output" wire or the splitter output wire as appropriate. (No, you can't leave the splitter in the line; it won't work.)
Connect a second LNB port from your dish to the "Cable In" connection on the outside of your RV. Connect the second receiver to the coax wire that currently runs to the TV antenna input.
Hopefully you can connect both TVs to their receivers with HDMI cables, and you're finished.
I'm sure this is very confusing, so please ask any questions.