stock fill location with underbed tank...possible or no?

[freezmcnally]

I've tried searching this but it doesn't seem like anyone has done this. im interested in doing an underbed tank but would like to just run rubber hose from the stock filler to the tank (for flex) .....is this possible or would there be venting/fill problems?
if it won't work i will consider (and already know) all the other options, but i kinda like the original fill location.

i have a 68 long bed with wood