My advice....
First, figure your cost and then double it and don't be surprised if it is triple when you are done.
Second, everything will take a lot longer then you figure especially anything you have someone else do.
Third, you will never get your money back. The car's true value will never exceed what you spent to restore the car.
Fourth, it is much easier to take the car apart then it is to put it back together. Organize everything as best you can. I use a lot of those plastic food containers that you can buy in the grocery store. Label, take lots of pictures and notes. Not everyone will be familiar with a 57 Imperial like they might with a newer car, so you will have to depend on yourself to put it back together the right way.
Here's my best advice though... get the car running and driving first. Tackle one area at a time while you are driving the car and having some fun with it.