Robert,
On mine you can loosen the tank and then tilt it down enough to get to the top. I drove the MH up on ramps lifting it 4 1/2 inches. I then raised the coach to full ride height the blocked between the frames. I put the jacks down and then placed other jacks and blocking around the frame.
At this point I got a motorcycle jack and slid it under the fuel tank. I loosened up and then removed the straps and lowered the fuel tank until I could get to the top. With everything blocked up it wasn't to tight under the MH. The more fuel you can get out the better! I had to buy 2 55 gallon drums since mine was full at the time.
Hope this helps you some.