Replace Body Parts Or Repair!

It would really depend on a few things, the major one being how bad the current rust is on your vehicle. Second would be on how good you are at basic body work. Some more info would be helpful.

The hatch is prone to internal rust. If it's bad ; replace it. Have you looked into stripping the fenders and hood. That hot caustic will take care of the surface rust and paint! Might be less expensive.

I had a hatch from hell when I first bought my car. The whole back end where the trunk key is located was completely gone!. However I have a Brother thats a pro at bodywork, and we completely remade the hatch backend. It looks pretty good, however once I see it start to fall apart again I will replace it. Body work is an art and takes some time to nail it. If you can get all that stuff for that price your doing pretty good. Its hard to find matching body parts with matching color. I may sound silly but I love taking time to do my body work. I crank up the metal tunes and go to town when I do body work. I also have matching paint color so its look pretty good. Anyways thats my opinion.