too much rust?? too much work??

[GMC-YA68]

Ive been scouting for a 67+ shorty. Ive looked at a couple and it seems almost all of them have the cab supports rusted out on them, the rockers and some of the floor...The cab was sagging on one truck because they were so rotted...Would you say these trucks are going to be too much work? Just trying to get some input, i know people have built tons of em. This is going to be my first, i plan on stripping everything and blasting it so keep that in mind...tell me what you guy think...thanks for the help.

Keegan