Mine has a quick disconnect fitting and yes, there should be a propane line run back there. It would be under the trailer, least ways mine is. But it won't fit what you want without getting some adapters and such. I almost did what you wanted to, but figured its just as easy to use the little 1 lb bottles for it or a big bottle with a bulk adapter. That way I can move it anywhere I want and am not stuck at a location where Jayco thinks I should cook
In the end, it's not needed for me. But I am sure you can adapt and fit it, if that's your thing.