Yep, pretty ugly repairs.
If it was me I might consider a complete rear lower cab panel, which includes the corners all the way around to the lock pillars and up to the belt line.
All that crap has to be cut out to do it right. A complete back panel would be the simplest, requiring the least butt weld joints.
Or you could slobber some more filler on it and hope the rust doesn't eat thru in your lifetime.
