I use food quality polythene pipe. 18 or 19mm will take all the standard Hoselock fittings. Get the thick wall, it won't kink.
With a clear pipe you can see if anything is trying to grow inside, black bits and then you know to clean with bleach or replace. Any garden hose can have all sorts of horrors inside!
I have one 2M section for when I am close to the tap and a 10M if needed plus the rest of a 25M roll which is sometimes very useful.
Also buy the cheapest screw connection for joining two pipes ( NOT Hoselock but cheap from a market ) it is a perfect tight fit for most water inlets on the side of your van, then the hose won't come out when you are filling up.
I have used different flat and stretchy hoses to fill a boat, 200 litres took 25 minutes, a hosepipe or polythene one the same length and from the same tap 7 minutes, it has a larger bore.