Alas, we are now too old to walk the Camino as a spiritual journey, but would like to at least glimpse part of the path and Santiago de Compostela before flying to Barcelona for a cruise. Is there a one or or two day trip company along a bit of the northern route?
What’s nice with the Camino is one can walk as much or little of it as one wants to. Not knowing what old equates to, you may wish to walk no more than 6 miles a day, or less/more.
Look at where you’ll already be on your trip. It’s possible one of the Caminos passes through it. If it does, start there. You could take a taxi 6 miles east then walk back to your hotel. The following day you could walk 6 miles west and take a cab back to your hotel. No changing of hotels would be required. My point is, there may not be a need to go through a company to accomplish what you want to do. If you want to visit Santiago you can take a bus or train to it.
The last stage of the Northern way is actually on the French way starting in O Pedrouzo, 12 miles from Santiago, and ending in Santiago. The last six miles is not very scenic with the last few miles being through the outskirts of Santiago to the cathedral.