Here is my free advice (which is well worth the money).
When subscribing to DirecTV, get a mobile subscription and optionally take it back and forth to your stick home. With this, you can qualify for Distant, nation wide (NY, LA) channels if you care for them. Sometimes they come in handy.
For HD you need the SL3 dish, which is, IMO, just as easy to set up as the round dish. This dish will need a heavy duty mount such as the tripod sold by TV4RV.com. SWM (single wire multiswitch) is, obviously, the easiest to install, when it comes to wiring the RV. However, SWM is a little more involved, when it comes to setting up the dish. People who use SWM each have their own favorite method of setting up, varying from baby monitors to $500 meters.
After trying many methods I have come up with my own method, which is a little unique. I swap out the SWM horn with the old legacy horn, just for the setup process. This allows me to use my old, inexpensive, self powered meter to locate the 101 satellite. With the 101 located and the skew preset, all three satellites (99/101/103) should be there. I then remove the legacy horn and drop in the SWM horn. The screws are optional but I don't bother with them.
Not arguing that my method is better than anybody else's method but just works best for me. With this method, using a self powered meter and a compass, I don't even need to run the coax to my RV until after I'm done with the setup.