This is why I never go to the Dr. You never go then theres never anything wrong.
Had you never pulled up the carpet there would not be any rust.

 

Indeed. This should be fun.

 

Holy Moly! That is pretty rough. I think the idea of just covering up the back may be just fine, but that front might actually need a new pan welded in. If you try to bolt to anything there it may just rust out in year or two, then you will be Flintstoning your butt down the road. WOW!

 

There is almost nothing to worry about. Where I live rust is so common that it is not an issue anymore. I buy old cars for demo derbies and I can count on my fingers those that still had floor panels. Most of the cars I buy are from between 1985 and 1999. A friend of mine once bought a Ford Tempo and the only thing left under the carpet was the subframe. Wish I had a picture of that!

 

You can grind away most of the stuff in the rear. If you don't, it will just continue to corrode under wahtever you do. Get a small air compressor if you don't have one and some air tools. You can even get a cheap paint gun and learn to spray it yourself.

You could take a basic welding course at a vo-tech school. Buy a cheap welder and you would surprise yourself with what you can accomplish pretty easily. It's not an undersea pressure vessel, pipeline, space craft or anything really critical. It's only an old Rover. You can do it.

When I was in college, I took one quarter of basic welding and learned quite a bit from it. A few months later, my wife had to have emergency surgery for appendicitis. Her job had been paying our rent while I was on a co-op program, working every other quarter and this was my next school quarter. I picked up the Atlanta want ads, and Frito Lay was advertising for maintenance techs, must be able to troubleshoot electronics and be able to weld. I left her bedside in the hospital, drove to Frito Lay and was hired on the spot. Had to start work that evening on second shift.

If you cannot make up your mind to weld in new floor pans, you can cut away what is rotten and replace it with marine grade plywood, cut to shape and bonded in. That would last a long time also. The older cars were originally built with wooden floors.

Henry Ford speced the shipping crates for his engines such that the lid of the crate became the floor board of the car on the Model A.