I was interested in doing this with our teardrop trailer and because of mistakes in its construction I had to redo the gas line from the 25# tank on the tongue and the galley in the rear. I also wanted to power a grill and chose a Bullfinch gas point from the UK which along with a shower point I imported. I see the gas point is now available on Ebay Bullfinch Gas Outlet Point | eBay
However if you do not wish to be this elaborate I would try for a local gas grill retailer. Mine made up the 10' hose and gas quick disconnects and adapters on the grill.