Montserrat is very easy to get to from Barcelona by train. There are also day/half day bus tours available we love our sleep and the cable car up to Montserrat looks fun. Take the R5 train at Plaza Espanya. At the station, you could buy the combo ticket of train + cable car or train + funicular tram (there are also various options of getting museum tickets, meal voucher, etc.). The ride up was about 5mins, there are only two cars.
The famous “black Madonna”. The queue to get close and touch the statue was extremely long. It took us 2hrs! If you don’t have enough time, you can still see it from far inside the cathedral.
We then took funicular tram to go higher up the mountain. There are a number of walking trails around the mountain.
We took the 10.40 train from Barcelona and returned with the 16.30 train. Still have plenty of time for other things until sunset!