Okay but where do you leave your (rented? ) bikes after two or three days ?
I guess you ride 60 kms a day so after 3 days you are almost near the Spanish border.
From there it is about 100 kms to Santiago. So with an average walking speed of 20 kms per day you will be in five days in Santiago.
(Edited) Now I read your initial post again.
your rental bikes will be picked up.
If you ride and walk the Central route I - if I were you-ride as far as albergue
Casa da Fernanda (two days riding) and walk from there
day 3
Casa da Fernanda to Ponte de Lima. 14 kms Beautiful town
casa da Fernanda is between Barcelos and Ponte de Lima (18 kms from Barcelos) in the village of Vitorino dos Piães situated at the waymarked path .
day 4 Ponte de Lima to Rubiães 18 kms off road terrain going over a mountain of 450 mtrs altitude
day 5 Rubiães to Valença do Minho (20kms). Or Tui (Spain ) 23 kms
day 6 Valença/Tui to O Porriño 20 kms
day 7 O Prrińo to Redondela 19 kms of (adviced Cessantes 22 kms (stay at o Refúxio de la Jerézana
day 8 Redondela/Cessantes to Pontevedra 20 kms nice town
day 9 Pontevedra to Caldas de Reis 18 kms
day 10 Caldas to Padrón 20 kms
day 11 Padrón to Santiago 23kms or alternative
walk to Teo a Casalonga of Milladoiro. ( max 13kms and have
an easy walk next day to Santiago
From Santiago is a bus (ALSA bus ) back to Porto airport and Porto Center ( metrostop Casa da Música)
bom caminho