Not a ton of experience biking in the region, but I rode from Barcelona to Montserrat and it is quite lovely. There are a few sections where you're on a road busier with cars than one would like, but I've found Spanish drivers to be fairly respectful of bikers*. It was about 3.5h there, 2.5h back, with a nice 600m climb up the mountain at the end of the trip. The views up there are simply stunning.

* Fun story, I rode 1500 miles throughout Spain ~10 years ago, and had not a single bad experience with a motorist. When I got back to my home in NY state, literally on my first bike ride back, within 2 miles of my starting point, a man in a truck threw a beer can at me.