I got rust. Passenger side rear floor pan is crusty and has a pretty ugly hole. What do I do? I know there are many out there who have dealt with the same problem, how'd you fix it?

Is there a place to get replacement floor pans, or is cutting them out of a junk yard car the only way I'd get one?

Is there a fiberglass product that is strong enough for the job?

There's an overlapping piece of steel under which runs the rear floor heating vents (I assume) - does that un-bolt (please say "yes") or is it welded in?

Would steel from galvanized heating duct be thick enough for the repair?

Finally, what's a good way to get that sticky plastic matting up so I can see how far the rust goes?

Thanks in advance,
Sean