[Mixed76]

Really depends how much time you have. 900 sf should be plenty of working room. Lift would be helpful but for this repair you really need a rotisserie.

Since this is a targa, and you've said the rockers and floors are suspect, you'll want to weld braces holding the front of the car to and in alignment with the back.

To keep the frame from bending (or even sagging), and from spilling fluids when you rotate it on the rotisserie/ start cutting metal off, you should take off engine, transmission, doors, battery, fuel tank, oil tank, wheels, maybe the glass. Fenders and lids might be a good idea too.

Then you'll want to have a good system for measuring and aligning parts as you cut out and replace.

All this takes time, care, thought.

Can it be done? Yes? Can you? No idea. For me it would be an impossible time commitment and a path to a car that gets sold in pieces a few years later.

Just my opinion.