Inner Rocker (behind rear floor support) Replacement
 

My cab corners are in good condition but if I reach my hand down in the cab corner, there are large holes in the inner rocker (assume this is still called the inner rocker back to the back of the cab?) and I can stick my hand into the rear floor support. I do not want to cut out my good cab corners as the replacements I have seen don't line up well and my floor support is pretty solid too but I would like to address this rust. I replaced both inner rockers behind the outer rockers as well just not all the way to the back of the cab.

My thought is to cut about 4" or so of each rear cab support end off, unbolt from inner rocker, weld in a new piece of flat steel in each corner, then weld the floor support pieces back on, and bolt up by reaching the bolts from inside the cab (stick hand down into the cab corner from inside). Does this seem feasible? Any simpler ideas to address this that does not involve hacking up my good cab corners?

Re: Inner Rocker (behind rear floor support) Replacement
 

Sounds like a great plan.
They make a lower B-pillar patch.
You might consider adding it
to your extended inner rocker
piece for even more strength.
Sounds like it may be gone
like on most trucks.
I can post pictures later of one
of the patch panels if it will help you.