Well it's been a long time since I've even been around an Eagle so I ain't really got any easy advice for him on how to do it! But I strongly suggest NOT tapping into the supply line for the engine! It has really been along time for me on an Eagle and I'm try'n to remember if theres an access panel in the floor that would make it possible to go thru, might not get him right over the top fo the tank but maybe close! the other option might be coming up from under the backside of the tank from underneath the bus to access to top of it! What ever he does he needs to be sure and leave his pick up for the generator at least 6" above the bottom of the tank that way the generator does not cause the coach to run out of fuel while boondcking! If the generator won't run because it's not getting fuel, time to head for a fuel stop! At least that is the way most prefer to do it!