New member from pacific northwest

It has some serious rust in some places I am concerned with ( window frame , door jam sill , heater/vent box ) . I have the original engine short block but no tranny . Need a passenger seat and probably a trunk lid . I already have fenders , 1 door , 1 bumper n brkts . How bad has rust got to be to not be repairable ( i already know money fix's everything ) without a ton o' money ?