An often overlooked point, when discussing restoration costs, is who will do the restoration?
A world-class restorer is going to charge a very different rate, to your local violin shop, which will be different again, to Billy-Bob's backwood fiddle shack. The end result you get, will vary accordingly.
It seems that restorers often get lumped together, as though they are all the same, and have similar abilities. This is patently not the case, and quite a few, have no place working on anything over €1,000.
So it isn't simply about the amount of work required. The skill of the restorer is going to be a massive factor too. Therefore, I don't think anyone can provide an accurate price to your question.