4 days Barcelona-train to Carcasonne or day trips nearby for old towns?

Check today's replies of mine here: https://community.ricksteves.com/travel-forum/spain/itinerary-one-month-in-spain-with-kids-30798935-c632-4537-9440-57be5310654f and also this one https://community.ricksteves.com/travel-forum/spain/barcelona-7-days and see if those links and suggestions help.

thanks. great ideas! C might be out and instead we stay in Girona for 2 days and day trip to Besula, and add Montserrat from B at the end. We also love to hike, although early Sept. might till be hot?

Hi Elaine...
Girona is a great base for day escapades (ie. Besalú, the medieval fortified town, reachable by bus (1h)) but also to beautiful natural places, be in the mountains (Catalan Pyrenees), like in the Cerdanya Valley, be in the coast, for example, hiking a bit of the Camins de Ronda....(check this old post of mine for further details about the later).

And if you were to consider renting a car, you could certainly splurge yourself with a fantastic route thru some of the most beautiful villages and landscapes, at a stone throw away from Girona, for example: (1) Gorg del Molí de Murris - (2) Olot Modernista - (3) Aiguamolls de la Moixima -in the outskirts of Olot - (4) Fageda d'en Jordà - (5) Route thru the (no extinct) volcanoes in La Garrotxa area: for info about Volcà Croscat, Puig de la Costa, Santa Margarida i Roca Negra check here- (6) Centre Historic de Santa Pau - (7) Castellfollit de la Roca - (8) Besalú - (9) Estany de Banyoles This is a route easily done in one compact day or two days at an easier pace.

Just sayin'

thanks so much. No Car. Must be accessible via train or (under 1 hour) bus ride. Can we get to Cerdanya Valley via bus? Also, should we just base out of Girona and forgo Tarragona? I can't see doing both in 4 days without being rushed.
Maybe overnight in B, then train in AM to G, next day Besalu, next day Costa Brava-just for hiking coastal trail--no interest in beaches (or go to Cerdanya if we can get public transit)? Then back to B and go to Montserrat?

To get to the Cerdanya, with using only public transport, one can travel as far as to the town of Puigcerdà, ALSA has buses that leave from Estació del Nord in Barcelona, and make the 3 hr trek up to Puigcerdà, however to further explore the Cerdanya valley beyond Puigcerdà, one will need to hire a car.

We just spent some time in Zaragoza. Pretty town, not heavily touristed. Plenty of interesting things to see. 1.5 hours from Madrid, by train. We didn’t have a car. I think there are some natural areas just outside the town but we didn’t explore them.

The Cefdanya Valley 0can get really hot in the summer. I spent several nights in Puigcerda in 2016, and the temperature was uncomfortablym higj. There are buses going to Llivia (to the NE) and several old villages to the SW. I also traveled to La Seu de Urgell, which has a very pretty historic center. From Puigcerda one can either taxi or walk (40+ minutes) to the French town of Bourg-Madame and take the SNCF yellow train through the Pyrenees to Villefranche-de-Comflent. A round trip is possible in pne day.

We've been to all the places you named, Carcasonne is a zoo during daytime tourist season, but at night it's magical. But since you have limited time, don't spend it all sitting in a train. You mentioned France, we loved: Nimes (3-4 hrs direct train from B) is great base. Side trip local train/ bus to Avignon, Arles or Pont du Gard etc... But for ease of travel and keeping transport cost low, you can stay in Spain, train to Tarragona ( 1 hour train), get a real feel of the "Spanish." Not many tourists but great roman ruins and food, more lay back. If you like amusement park or you have kids in the group, Port Aventura is 5 min taxi away or local train. Or spend a day at beach next town, Salou. Or train to Valencia (another 2-3 hours overnight there), so much to see & do.