Rear quarter body help needed

I think the best way to replace a patch panel is up to the guy doing the work, I have my ideas and the next guy might have another idea. Some may last longer than others but the finished job stands at you feel you did the best job you could.
I,m restoring a 1972 ford pick up for a guy that only wants the out side sheet metal to be nice he could care less about the back side, yea I told him what was gonna happen down the road but he did not care he could afford the nice paint job and couldn't afford to do it right. He told me he was not long for this world and wanted to enjoy his pick up for as long as he was alive.
I'm working extra hard to get his pick up done as soon as possible.
And I plan on trying to seal the rusty back side to make it last a little longer. not gonna make a lot of money on this truck but I know I'll feel good about what I did.