We still go to tractor supply or get it at the campground depending on where we are when we decide to fill.
As stated if they can fill portable then they can fill the installed.
The only difference is whether or not they have the room for you to park close enough to reach your tank.
Lynn & Dennis
Nights Camped 2017 - 35 / 2018 - 15
2014 3051S - First RV for us
2018 Hyundai Elantra Sport Toad
2015 Harley CVO (retirement bike
2015 Challenger ( Wife's Toy)