Why not go to the local U pull it and get another door 10 min and your done you'll spend more than the price on materials alone not to mention the 20 hrs of time you'll e wasting ...theres lots of those cars in the yards. and in all likelyhood it'll need pins and bushings anyway so why not just replace it...
and still get a respectable job
primer ...50.00 a qt
20 hrs labor
not to mention 50.00 worth of sandpaper (all the grits)
a good used door .....50.00
OH yeah and save THAT kind of work for something thats hard to find like a Mersadies ,LOL.
Seriously though Its good to see someone with enough confidence in themselves to think they can spread that much bondo & primer and have it look perfect or even good for that matter...