It’s not uncommon in older fill stations to find faucets with no threads or hoses with no male ends.
I have on occasion used a hose with the female connector cut off to slip over a smooth faucet and fastened it temporarily with electrical tape to fill.
For an alternative, I’d use a portable submersible pump in a bucket. Let the source water run in the bucket and pump it up to the motor home.
I’d have no interest at all in installing an old style gravity fill. We have a 100 gallon tank, there’s no way I’m carrying that many cans of water!
