I just finished the installation of a DirecTV setup in my 2001 Safari 25. I modified the wiring to allow dual use of the existing Cable TV input for campground cable and the satellite dish. I added a 2-jack connector plate adjacent to the existing preamp/cable switch and jack plate inside the cabinet aft of my refrigerator. I mounted a 2-way ANTENNA/CABLE switch and the DirecTV B-band converter on the wall of the cabinet. With the switch in the ANTENNA position the external cable is connected to the DirecTV receiver which is connected to the TV by HDMI. In the CABLE position, the external cable is connected to its original location on the preamp jack.
I mounted the DirecTV receiver to the right of the TV on the wall above the cabinet. In the picture below the TV is pivoted to the left so you can see the DirecTV receiver. When the TV is pivoted back to the right it hides the DirecTV receiver, except when seated you can see the bottom inch or so. That was fortuitous because it is just enough to allow the IR remote to work. I thought at that angle I was going to have to buy an RF remote.
I bought the 3-LNB Slimline dish as a package from Satellite Oasis. It comes with everything you need including the dish, a tripod, a cable and an alignment kit with a compass and a signal meter.
DIRECTV Triple LNBF Satellite Dish Tripod Kit for RV Tailgating - Satellite Oasis
Al