If you have lots of space, time, money and perseverance and of course some mechanical talent, it can be rewarding. On the other hand, if you are doing it to increase the value, it most likely will NEVER be worth the time and money you put into it, at least not for many many years. If this is something you are going to keep in the family, then it may be worth all of the effort and money.
I'm on my third body-off restoration, doing my daughter's 72 LT-1 convert that she drove to college. It's a have-to situation since it is completely worn out. Once you start working on these old cars, you just keep finding other things that need to be fixed. I haven't done a detailed cost estimate, but I suspect it will be $10-15,000 even with doing everything myself, including the painting.
Good luck if you decide to undertake this project, but really take a hard look at the costs and time committment involved, not to mention it takes at least a two bay garage to do this in with some comfort.
Ol Blue