Even more rust under the carpets of my K5

Man i tseems like every single time i take something out of my truck to see what kind of shape it's in underneath, i find more damn rust??? what's the easiest way to patch all of this rust, so it will either permanently kill it or atleast slow it way down. People say Toyota's are bad for rusting?? my last toyota had half the rust of this 85 blazer and it was 4years older and driven one heck of alot harder? Today i removed the rear panels off the box sides and surprise yet again more rust?? so now i'm up to the boz having holes in it, tailgate being toast, and inner box sides being rusted out pretty good?? yet the cab has nothing?? how should i go about repairing this in the best and most cheap way to do it?? I will be boxlining the interior then custom carpeting everything

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Project MudhuckerII is now underway and movin ahead