Just got back from two weeks in Spain (including a two night side trip to Carcassonne, France) and the book and these forums were a valuable resource. I just thought I would share my thoughts hopefully to help others.
First, the preliminaries. For the fifth trip in a row, we needed no euros at all. "Tap" worked everywhere. (Except a minor thing that was all my fault). Second, the transportation in Barcelona is a joy. The subways are fast and clean and crowded but felt very safe. Once you learn the system, you can zip around almost anywhere (and for sure hit all of the highlights). Third, on those occasions when we needed a taxi, the "FreeNow" app from Lyft worked like a champ.
Now, the particulars. We stayed at the Hotel Continental as recommended, and for budget traveler or those with large families (we were there for a wedding, so the pre-trip sightseeing had as many as five different family groups), it's a perfect choice. The staff is AMAZING. The hotel is old(er) but is in a great location on Las Ramblas just steps away from Plaza Catalunya and so many great streets, shops, and museums. We loved the convenience of the 24h buffet, especially in the morning. Would definitely stay there again.
Besides general shopping and sight seeing, we did seven "attractions" listed in the book:
1. Sagrada Familia -- not to be missed (this was my third time) and having a semi-private guide for about $70 per person was definitely worth it as we not only skipped the long lines, we also got some great insights into the history and architecture
Picasso Museum - my second time there, and I enjoyed this visit way more. In fact, I only remembered the last room. Has the rest of the museum been updated in the last ten years? Nothing was familiar. Definitely recommended.
Nova Icario beach - first time there. We went for the quieter, kid-friendly beach, and this was one of the top highlights of the trip. We are used to beaches in the Gulf South, and it's quite different, but the two grandbugs spent hours just frolicking around and even made friends with Spanish kids there on a field trip. Definitely recommend.
Chocolate Museum - second time there. That one definitely changed for the better since last time, and my grandbugs loved it. We have a cool picture of them next to the same sculpture from the movie Up as in a picture with my youngest son when he was about their age back then.
Montserrat trip - third time visiting. We finally got to see Montserrat in good weather! We bought the "Tots Montserrat" card, and it was so worth it. For about $80, you get subway, train, aeire, museum, basilica, free trip to the buffet cafeteria for lunch -- basically everything you would want to do to see Monsterrat from Barcelona in one cheaper price, and with no lines.
Park Guell - third time, and first time with beautiful, sunny weather. We only had time for about an hour, but it was enough to see the hill, rosary walk, the main garden areas (including some cool parakeets!) and the look out point.
Mercat Boqueria -- first and last time. Honestly, very disappointing. Sure, it's fun for a few minutes to see all the stuff, but most of the food was overpriced and reheated in microwaves. Had we not gone in with the idea of eating there, maybe we would have enjoyed it more. We saw, but didn't linger, in other mercats that looked much more interesting.
Lego store (Placa Catalyuna) -- we did this one because our grandkids love Legos and we had just as much fun exploring the place and making a little Lego person.