ok so I want to paint my car in the spring but it has rust thats ugly to the eyes, before I paint it I want to fix the rust but I dont know how to get to it ( its above the door hinge) should I remove the doors ??? and how ?
also I have rust on both doors

You need to look very close at the windshield frame around the VIN number, Do you see any rust? if its rusted above the door hinges and the windshield frame it could be Bad.(Are there any cracks in the windshield).
But in the photo you posted it looks like every other C3 that's a spot that never gets finished out being it is so hard to get to. even when the car was new it had an unfinished look there. Is there holes rusted thru? its hard to tell. Take some more photos of the hinge area, windshield frame, remove one of the kick panels and get a photo of the body mount & bolt there.
And maybe a couple of the main frame just in front of the rear tires. Do this and i can tell you where to go next.
David Steele

my car grows rust and it only took 30 years to do it :-)
I only took this its the wost spots

It`s not that bad yet, We have repaired some that where 100 times worse but its time to fix your now. Just pick a starting point and fix one spot at a time when you have time. Trust me ( cant believe I'm going to say this) you don't want to have to pay a Corvette shop to do. You cant spend more than the car is worth.
David

thank for the advise i will put it in the garage for now to work on it (its 60F and am cold)