Although they do say that failing to plan is planning to fail, they also say that no plan survives contact with the enemy. I don't mean that the Camino is your enemy, but no matter how carefully you plan, something is bound to go wrong and your plans go out the window. The old Yiddish proverb, “We plan, God laughs,” or Man makes plans … and God laughs. (Proverbs 19:21) (It's not verbatim, but it's the gist of it.)
So I would advise you not to plan too much. Allow a few days more than you think you need before you book your return flight. Go with the flow. If you don't need the extra days, time to tour Santiago or carry on to Muxía or Finisterre. I also recommend Efren Gonzalez' videos. Informative and entertaining. It's not a race. Allow an extra day for Burgos and León, possibly Astorga too. If you can find a shopping trolley in SJPdP, buy one and put your rucksack on it. Carry the trolley when the going is too rough. But it will be a blessing when you are on tarmac. I used a folding trolley on five caminos. [Foldable-Luggage-Carrier-Bungee-Shopping]