Rear cross member removal HELP!

[SoFlaFiat]

I have been scraping and cleaning the bottom of my project for the last few days and in the process uncovered multiple rust holes in the area under the rear cross member. I didn't think it was in horrible shape structurally as the long trailing arm mounting points have reinforcement up the front and back of the cross member. But now, I'm not sure! I thought I would patch all necessary areas from the bottom but when I cut one area out, I found the whole cavity has flaking rust and crude. I can't stand to leave any of that in there and am therefore considering removing the cross member from the top and cleaning the inside, patching the holes under and stiffening the areas around the trailing arm mounting brackets and the e brake stand offs. So, has anyone done this? Am I foolish? Is it better to cut away the whole bottom area and clean it from underneath? Any help is much appreciated!!
Thanks!!

[SoFlaFiat]

Might have been a waste of time but this is what I decided on.



It's not too bad but now I can sleep at night knowing I took care of it.