I spent a couple of days sanding this deck and aside from a few boards that need to be partially replaced it is in good condition. I also plan to fill in a few holes with wood putty.
With the weathered surface I would suggest a product like restore. I have used this on several decks with really nice results for weathered decking. This will cover the areas you use wood putty so the repairs are invisible. My last home had a large deck that I used this on with the roller they recommended and it was an excellent finish and covered 3 diferent ages and types of wood.