There is old Roman road under many of those paved roads! First animals, then Romans, then horses, then cars. In many places the yellow arrows take you off the parallel path a bit further away from the road; sometimes land ownership gets in the way of such diversions. It is not realistic to expect any pilgrimage of such length that goes through cities to be a walk in the forest (especially when there is no forest as around Leon). Tendonitis can affect one's perception of the surroundings.
I have walked into and out of all the big cities, and I have taken transportation into and out of all the big cities. The beauty around me is more a matter of my attitude than the visuals around me. For example, leaving Leon one can get a
cafe con leche at regular intervals. Leaving Belorado in the trees, not so much...
I reiterate my recommendation that a pilgrim skip parts as a response to what he needs that day, not by a plan. I was walking into Leon one Holy Week, and the parades were assembling for the processions in
capirotes. What a shame it would have been to have been on a bus!