Looking for inovative ideas for auxillary fuel tank???

I gravity feed into the factory neck on my 5.9 , no connection to the vent or return line. If I forget to shut it off , nuttin happens .It does not run out all over the ground it just stops running . Mine is 1/4 inch and works fine . When I get down to a quarter tank or so ,I step out and open the valve in back of truck and let her rip for an hour or so .