Removal depends on what is going to be saved.
If you are saving the inner, then use a spot weld cutter along those edges.
Where the frame attaches to floor pan and torsion crossmember, I'd use a grinder to cut the rail away and grind flush. AIr chisel on the crossmember attachment. Much faster than getting the floor pan spots out with a cutter. The ones on the x member are a bear sometimes with a cutter, especially with all the stuff in your way.
I might also have a frame rail available for your car as well.
4404spd, nice work on the front clip
My inner fenders. Are kinda beat up whr the fenders mount is startin to rot and on the shock towers they r barely there...so i don't know whether or not that stuff is fixable or if its just worth it to replace the whole front clip with my dusters front. That duster one is in better shape has a few holes here and there that can be patched or if I should just buy new inners I found them on ebay for like 350 for the pair