I've just done this, catching the bus from Santiago to Cee. Some notes which may be of use for future walkers:
Finisterra to Muxia is no problem - alternate signs give directions both ways.
Finisterra to Hospital is described in detail in the
Brierley guide but you have to read every detail. I overlooked a (+.3k) note and walked a k in the wrong direction.
The mojones are very carefully placed and angled and you can usually work out where the path has come from. Signs that you are on the right route include the distinctive granite v- shaped drainage channels diagonally across the path and surfaced or segregated paths alongside roads.
Beware of assuming that anyone walking towards you is a pilgrim on the right path, especially at weekends. Other tracks intersect the Camino, and many people enjoy walking in this lovely area.
There are quite a lot of informal faded yellow arrows pointing to S or SC. They are usually on the backs of lampposts and similar and are helpful once you've got your eye in.
In a couple of places where things seemed unclear I got in a complete muddle trying to read across from mapy.cz which shows topography and the route, but not where you are exactly, to the
Brierley maps, not to scale, to Google maps which shows you where you are but not the route. Then a kind pilgrim burrowed under his poncho into his pack in the pouring rain to show me the Buen Camino maps on his phone. No more navigation problems.
If you do short stages there may be nowhere open en route to get a stamp. I just got two at my destination. It wasn't a problem. But no refreshment stop for 10-15 k could be if not prepared.
The approach to Santiago is lovely. A great view of the cathedral, then greenery and a very short urban stretch through attractive streets and straight up into the Obradoiro.