Welcome to iRV2. Your engine is a 460 CID. Sounds like your talking about the fuel filler line. If it is, it's similar to my 99 F53 and has the filler at the rear of the coach. If that's what you have, there's probably is two pieces of hose. One just past the filler port and the other where the line connects to the tank. There is a 90° turn just before where it connects to the tank. I really doubt you would be able to push a hose down the line to the tank. If the one that is leaking is the one near the filler port is easy to get at to change. If it is the one at the tank it's a little harder to get to but is do able. If you know someone the handy with stuff like that, you can get the fuel hose at NAPA and some other auto parts stores.
BTW, you may want to join the National RV owners forum and the Ford Chassis owners forum. You can get a lot of help for both the coach and chassis on those forums.
Chuck & Teri, 1999 35 ft. Dolphin 5350, F53 Chassis with tag axle, Chassis build date 1/99 in Mexico, Banks System, Trans Command, Air Lift Air Bags on rear, Koni Shocks, Blue OX TruCenter, TigerTrak track bars front and rear, Roadmaster 1-3/4" rear auxiliary sway bar, 2013 VW Passat TDI SEL Premium, 1994 36 ft. Avion 5th Wheel. FMCA #F430129