Hi, I’ve done both and preferred the inland route.
The route by the coast looks nice, but its asphalt the whole way, on roads through residential areas.
The inland route was quieter. Also a lot of asphalt, but more villages, and up and down in green areas.
If you decide to take the coastal route, then I can recommend forking right at the river, Rio Lagares, as the path then follows the river all the way up to the football stadium, Estadio de Balaidos. You’re in the Vigo suburbs already, but it’s quite pleasant with plenty of joggers and dog walkers.
Jill