Robi, between October 19th and November 10th I walked from Barcelona to Pamplona via San Juan de la Peña, the reason I chose that route. It took me seven days to get to Tárrega. In the spring the route could be beautiful with green fields and flowering orchards but things were a bit drab and dreary for me with the fields already plowed up. After Huesca things got a bit more colorful with some autumn color in the foothills of the Pyrenees. The scenery along the Aragonese was nicer, more green.
I've hiked a lot in New Hampshire's White Mountains so the few days in the Pyrenees was no problem. So if you hike up there you shouldn't have any concern with that stretch.
On the Catalan, after the stretch coinciding with the eastbound Camino Ignatius, I met only one pilgrim for one night and one hiker using an albergue as a base camp. From guest books it looked like the previous walker was three days ahead. On the Aragonese most nights were spent with the previously mentioned pilgrim and one other. I suspect the trip along the Ebro will also have few walkers in autumn too though.
From the base of Monserrat you could walk up (though it is steep) or take a cable car. There is an exceptional art museum up there.
And here is how to get in touch with the Boston chapter of the American Pilgrims on the Camino.
The Boston Chapter of American Pilgrims covers the general area of eastern Massachusetts, but also welcomes pilgrims from greater New England. Formally accepted as a chapter in Spring 2012, the Boston Pilgrims have the distinction as being the first chapter east of the Mississippi.
They were going to have a hike in the Blue Hills today but postponed it until March 13th due to today's snow.
Enough for now. Welcome aboard.