When is too much is too much (rust)

[BigOrangeTruck]

I have a 69 stepside that I currently use as my daily driver, i love the truck and plan to slowly restore it...however due to my own perfectionist issues I am going to have to contract most of the body work out.

My question is this...
How much rust is too much when it comes to the cab , what is considered repairable, when does it just make more sense to find a new cab.

I have rust issues in:
the back corners (which seems pretty common)
floor pans (again pretty common)
Across the top of my winsheild. This is really the one that scares me..right now I have silicone keeping the water from coming in.

I love this truck and plan to fix it one way or the other, Im just looking for opinions on doing it well.

I will try to attach photos later.

Thanks in advance for all of your help.