It sounds like you've got it figured out then.
I would never recommend spending $1400+ for that Winegard automatic (nor would I want it mounted on the roof where I'd have to never park under trees...but I don't think you'd have to mount it).
The dish on a tripod is what you need, and yes, it's harder to align than the SD dishes, but we have several people on here that do it.
If you want an automatic solution, I'd suggest dropping DirecTV at home and switching to Dish.
Of course you could just set up a Dish "pay-as-you-go" account just for your RV, but that will set you back at least $50 for every 30 days of use vs. the free "take the receiver from home" method.
While we're talking about "antennas": You need to install the Winegard "Wingman"
onto your OTA TV antenna (trivial to do) or the Jack replacement head
. These will give you much better OTA reception for UHF stations.