Trying to visit Madrid, Barcelona and San Sebastian in 7 days is crazy unless ypu're just ticking off boxes and not having much time to relax and enjoy. Adding on Daytrips from Barcelona and San Sebastian is crazy. 7 days is somewhat short to try to even visit two of these places much less all 3 - especially if you're traveling from somewhere that you'll need time to recover from jetlag.

It does seem a bit much - could you do just Barcelona and San Sebastian? IMO those two have more to offer than Madrid and probably the weather would be more tolerable.

Also suggest that you stay with Barcelona and San Sebastián with only seven days. And a good idea to fly from Barcelona to Bilbao, spend a day/night? there with the Guggenheim, pintxos in the Casco viejo/Old town etc before heading on to wonderful San Sebastián. I would have done 3 Barcelona, 1 Bilbao and 3 San Sebastián.

Do you have your flights yet?

Unless you have access to teleportation devices straight out of Star Trek, this will be essentially impossible.

I agree with kimhe -

WE stayed one night - 2 full days in San Sebastian though and felt like we experienced a lot - many great pintxos etc...

Madrid can be beastly hot!! I would concentrate on Barcelona and San Sebastian and maybe explore some of the fishing villages nearby - it is gorgeous in that area.

Draw a line East-West across Spain passing thru Madrid. Now choose above OR below the line for your trip. In July, this is a no brainer, I would not go nowhere near Madrid or below....

Crazy, doesn't make sense to me.

It is a VERY common to overestimate how many places one can visit in Spain, and to underestimate how much there is to see. You kinda had an inkling of that, or you would not have asked if you were crazy. I hope you will return when you and your sister had consulted some websites or guidebooks to pinpoint your priorities on this list. Make sure to consider your budget, as the more you move the more you spend (often anyway).
Remember, July is high season for air travel and so just getting there is likely to be the bulk of your budget. I never start planning a trip until I have done airfare research and know if I am going to be able to snag an affordable airfare.
Finally, consider visiting EITHER Barcelona and its surroundings OR San Sebastian/Bilbao and that region. I say those two and not Madrid because in summer you may want to visit the coast. You "tick more boxes" that way, so to speak, and then next year you can visit the region you skipped and not feel like you have to traverse the country. good luck!

Spain is larger then you might think. We took a Traflager bus tour and spent a LOT of time getting from one place to another.

Rob

Yup, I think you'll be stretched doing that, especially with the side trips you mention.

Can't help but feel Madrid is being maligned here needlessly - I love it, and think it's the equal of Barca, although the two are very different. The points about it being hot in July are accurate, but you may enjoy 30C - I know I do (must be because we see so little sun in Scotland!).

I'd recommend two places in 7 days, either San Sebastian/Barcelona, or if you don't mind the heat, Madrid/Seville. The trains are pretty good for getting about, or at least, they were last time I used them.

One last point - by the time you get to Montserrat, have a good look about etc and return, it'll be more than a half day! Plus, it can get very misty there, obscuring the views - check the forecast before you head off.

mabanana-- I advised against Madrid this time because of the hote weather; I love Madrid; you can have Barcelona!

sometimes . one gets a feeling that a bran new poster might be "pulling" our collective " chain"

Viajero2 - No worries, I love them both

No - the number of brand new posters trying to fit 20 pounds of stuff into a 10 pound bag is legion.

It is the classic mistake many first time travelers to europe make - since they look at a guided tour (which can cover much more territory than you do independently since the guide and driver do most of the heavy lifting and people sleep a lot on the bus) and then add on more things they can't resist.

Also - I think many people underestimate how truly hellishly hot Spain can be in the summer - 100 or more in Madrid and 110 or more in Seville - and the number of venues that don;t have AC - including the outdoors. (We love southern Spain - but do it in April to get decent weather.)

Can only agree to limit your trip to 2 places - and check out conditions before you go - unless you love heat (I can't stand it).