Yeah, that's the wizz-bang fuel return plastic fuel hose, covered by a bit of rubber hose.
There's a coupling about 2 feet along the pipe back towards the tank, which IIRC is up around the diff and held in place by a lot of little brackets each held in place with a small bolt. If you don't want to cut the hose off at the sender unit end and shrink fit the plastic hose back onto the sender later, you can disconnect it at the coupling.
If you reckon the sender unit is crapped-out rusty, I'd cut it and save the agro.
If you reckon the sender unit's in good shape, it might be worth going through the hassle of disconnecting that return line at the coupling under the car.
Dave Barton has the process documented on his pages.
