The discs being rusty wouldn't bother me too much at this stage, but i would be inclined to jack the car up, take the pads out, and exercise the pistons a few times, lubing things especially the sliders up as you go.

Similar with the drums, i'd have them off and make sure the cylinders are all operating freely and the parking brake cable is free, do this by holding one shoe in place whilst an assistant operates the brake pedal gently, then repeat with the other shoe, obviously only take one drum off at a time, againa little lube where needed.

You'll know within half a mile if the discs are going to clean up properly, but unless really heavily pitted i wouldn't bother changing them until the car needs new pads anyway.

I hope it hasn't been left with the parking brake on, similarly hope the clutch plate hasn't rusted solid to the pressure plate.