Train or Plane from Barcelona Seville to Valencia then train to Barcelona

Hopefully, this will help. Go to Kayak site as advised in Rick Steve’s book and you will see that you can fly for around same $$ as a long train ride. About 3 hours less spent traveling. I just checked for flights from Seville to Barcelona and was pleased to see fare (with checked bag) around $130. . I typed in on site that I wanted flight to go to main airport in Barcelona (BCN) as I had read that some smaller airlines flew into smaller airport 60 miles N of Barcelona. Now, I just need verify that my flight does take me to BCN that is only 8 miles outside city. Good luck!

You can't do anything about the heat if you're stuck with an August timetable, but you can do something about having only 1 day in Barcelona, 1.5 days in Seville (both of which are world-class destinations really needing at least 4 nights) and 1.5 days in Valencia. Yes, you should drop Valencia. Sorry, but it's true. (Unless you're visiting family or friends there.)

Barcelona - Seville: generally 6-7 hours by train
Seville - Valencia: about 6 hours by train
Valencia - Barcelona: over 3 hours by train

By the time you add the time to check in and out of hotels and travel between hotels and train stations, you will have spent about 2 out of your 6 days (which are really 5, given possible jetlag/sleep-deprivation on your arrival day) in not-sightseeing mode. Do you want that kind of trip?

Yes, you might save an hour or so by flying in and out of Seville, but probably not much more than that by the time you get to the airport 2 hours before departure time, etc.

If you're as concerned as I would be about the heat in Seville, you could drop that city. It wouldn't be a bad decision to spend all six nights in Barcelona, which could allow for some time at one of the local beaches and perhaps a day trip.

I understand that most travelers are enamored with Barcelona, but I'm just not. I much prefer Valencia. It's a wonderful city to walk around, the Jardín Botánico is something no one should miss, and the Ciudad de las Artes y las Ciencias (especially L'Oceanogràfic) is just phenomenal.

I also wouldn't miss Seville, as it's just gorgeous with phenomenal history. But chacun à son goût.

As for trains vs planes, keep in mind that travel time must consider transit from airports to the city centers for all the fun stuff. That makes Spain's excellent high-speed trains a much more competitive option. Just something else to keep in mind.

If you have already bought your tickets (ie flying in and out of Barcelona), I would also suggest spending all six nights in Barcelona. There are lots of things to do in Barcelona and you can do day trips to the surrounding areas, including Montserrat.

How old are your children and would they prefer to stay in one city and take their time to see a lot of stuff or would they prefer waiting at airports or train stations, lugging their baggage all over the country and sitting for hours in a train or a plane?

If you have not already bought your tickets, you might consider flying open jaw, e.g. fly into Barcelona and fly home from one of the other two cities that you are interested in (assuming availability and affordability). You should limit yourself to Barcelona and that second city, but even then, your itinerary would be very rushed. Whether you take a train or fly between the two cities, you will end up using up almost a full day to transfer.

Good luck.