I walked between Lisbon and Porto and also between Porto and Santiago, all on the central route. The routes feel quite different. There are enough albergues now on the route from Lisbon and the way is getting more and more popular, so most probably you won't be walking there alone unless you want it. Regarding Lisbon to Porto: it is much more physically strenious, very long distances between towns all the way to Coimbra, absence of cafes and water fountains on the route sometimes for many kilometers, so you need to carry extra water there. Plenty of cobblestones to remember and a lot of road walking. The spirit of Camino that you feel after Porto on the central way is not yet there as for most of the Portuguese the only Camino is the Camino to Fatima. The route is still enjoyable, I loved nature there, especially between Golega and Coimbra. After Coimbra is goes more urban/suburban and a lot of fences everywhere. I'd rather go to Fisterra/Muxia. I remember the best for me was splitting the walk between two and stayin in the albergue in Lires. The most tranquil and picturesque beauty there. The best thing to finish your Camino.
