First, on the positive side, congratulations on locating such an excellent specimen of a shell. Whatever happens with your adventure you have the pleasure of knowing that the paint is put on a stong, rust and accident free base.
Second, I suggest that you take a look at http://www.horizonweb.com/wwwboard/Spray_101/wwwboard.html
This bulletin board concerns itself with spray painting cars and there is a wealth of information contained there. Plus you could post any questions that you may have to Len and probably receive an answer within a few hours.
If you were to ask there what the procedure should be for your car the answer might be:
1. Strip the paint to bare metal (done) 2. Perform all welding and major sheetmetal bumping (done?) 3. Clean, clean, clean the metal and give it a prep wash, then prime; or skip the prep wash and prime with an etching primer. 4. Maybe seal the primer with an epoxy primer, maybe not (how compulsive are you ?) (somewhere in here you fit hood, doors, etc and check for fit) 5. Spray on a high solids fill/sanding coat, cover this with a contrasting color guide coat. 6. Block sand until flat, if you sand through the sanding coat, repeat steps 5 & 6. Note: Step 6 can take a long time. How perfect do you want the finish to be ? 7. Seal the primer/surfacer/guide coat, then 8. Spray on the color coat; depending upon the type of paint chosen (lacquer, acrylic enamel, urethane, etc.) this might be the final coat or it might have to be clear coated. 9. Polish the paint (depending on the type of paint this might not need to be done, might have to wait several months).
The quality of finish on a car is a very subjective thing. How nice do you want it ? The extimate that you were given doesn't sound all that out of line. If you negotiate the price down the workman spends less time on preparation. Only you can determine the level of quality that you want to afford.
I will second Jarrid's view that you might want to at least consider doing some of the work yourself. Talk with your paint/body friend. I have performed body work (bumping/straightening through painting) on a couple of vehicles and I enjoyed it. But it did take me a long time.
Some of the major drawbacks to painting IMO are taking the car apart (yours is already apart) and the threat of having to do major body work, which as Chris pointed out is sometimes tough, (but your shell looked very straight).
Good luck ! Have fun. (Maybe AAA would be willing to give you some more money if you ask nicely ?)
-Roger