Another Q. for the suburban/Panel Gurus!

[big blue 72]

On the suburbans and panel truck, I have to replace part or all of the rear inner wheel wells on my panel.. They both have some rust.
So, what is available? what have you used and where from.
I have just got the new rear tail light sections and am ready to weld them in ,but need to repair/replace the inner wheel well rusted spots first.
So, any suggestions other than cut out the rust and weld in little round and square patches?