By the picture it doesn't look that bad. Remember it is an old gun and should show some character for its age.Maybe a real good cleaning would do wonders. It isn't a high value collector gun right now, but will be even less so once refinished. However if you want to restore you should strip the stock with a finish remover first. This hopefully leaves you with only having to do minimal sanding. You don't want to alter the contour of the stock. For gouges or dents, try steaming them out with a hot iron and damp cloth instead of sanding. You don't want to remove too much wood. Any real deep gouges I would try and fill or leave as it is an old gun. Then my personal finish of choice is a hand rubbed pure tung oil finish, not true oil or Fornbeys tung oil finish. There is hardly any tung oil (if any) in it.
For the barrel you have to remove all bluing with either bluing remover or emery cloth, changing to a finer grit to remove scratches. If you want to remove deep pitts you may have to file them out and then dress the barrel. All grease, oil and dirt must be removed from the metal with denatured alcohol or similar cleaner or you will get a crappy job. Do not touch with your bare hands. I would try and get rust bluing as opposed to cold bluing and follow directions. While you can get good looking results with cold blue, it has a tendency not to last, especiall if used in harsh weather. Rust blue is a slower process but quite durable. Again, this is only how I do it. There are other methods and ideas out there.
Do you have the bolt for this gun?