I have replaced my fuel filter with OEMY's product, and understand the problem. On my chassis, a W22, there would be room to cut the fuel line, and install a flare fitting, if you do not have enough slack in the line to go to the fuel filter, you could then splice in a intermediate piece. I personally would do that before dropping the tank. Dropping the fuel tank is a big project, been there and done it on another motorhome. If you decide to cut through, it would probably be through the basement passthrough, not the bedroom. Working headroom would be tight, but I have thought about that if I ever need to replace the fuel pump.
2005 KSCA 3778 on 04 W22 with Koni FSD
Banks Headers, 503 CID