Filling large propane tank on the road

Propane and fireplace stores that have a large tank on the side of the building, hardware stores, propane gas places, etc. Lots of places. First time I got mine filled, I was passing by a real nice looking fireplace and outdoor patio accessory place north of Albany GA. I turned around and went back and spied a large tank next to the building, so i went in and asked and the owner said he too owned a motorhome and yes, just pull it up. I told him the dealer filled it when I bought the mH and had no idea what I had used. Seem to recall I took about 5 gals was all. Ace Hardware Apalachicola FL has a tank next to the building, I spied while eating next door. I walked over and asked, they said they filled RV's all the time, so you just gotta keep your eyes peeled for the large tank.

Charles