11 days/11 nights flying in and out of Madrid

It's definitely doable, but importantly, when are you planning on visiting Spain? That would be helpful for further critique/advise.

Arrive Apr 28, depart May 9 Thanks!

Salamanca is rather far from Madrid for a day-trip, especially considering the size of its historic district. However, there is a 96-minute train option if you are prepared to get yourselves to Chamartin Station early enough for an 8:55 AM departure.

There is truly not much to Avila; I would skip it since your time is limited and you have a lot of potential day-trips. Toledo is the most interesting and is worth an overnight. You could also add Cuenca and Alcala de Henares to your list. Cuenca, however, is viable only if you take the AVE train, and that will be too expensive for a day-trip unless you're able to buy a cheap (non-refundable) ticket way in advance.

Zaragoza is often blistering hot in the summer, but I'm guessing you didn't find a $317 fare in the summer. If this is a winter trip, I'm not sure what Montserrat and Cadaques will be like (though they might be fine). Four nights in Barcelona is pretty minimal. You may or may not decide you have time for day-trips there. Many of the most popular sights pretty much require that you buy tickets ahead of time (to avoid very, very long lines), and it's hard to cram a lot of sights into a few days when you're having to guess how much space to leave between them. The problem sights I'm aware of are: La Sagrada Familia, Parc Guell, Casa Batllo, Casa Mila/La Pedrera, Palau de la Musica Catalana and the Picasso Museum.

We will be there Apr 28-May 9.

In that case, I would recommend you drop your current itinerary and instead make the focus of your trip Andalucía, the region of white washed towns and Moorish castles. If you have never been to Spain before, Andalucía is what many would consider the most quintessentially "Spanish". Spring (April/May) is the perfect time (weather-wise) to visit Andalucía too. In April, it can still be a bit chilly in some of the northern places you would like to visit, like Zaragoza or Cadaqués. I would save your current itinerary (Madrid-Zaragoza-Barcelona), which is a good itinerary, for September/October.

Instead I would do something like this:

Fly in to Madrid
Madrid (3 nights) - Day trips to Toledo and Segovia
AVE high speed train to
Sevilla (3 nights)
ALSA Bus to
Granada (2 nights)
ALSA Bus to
Córdoba (2 nights)
AVE high speed train to
Madrid (1 night)
Fly out of Madrid

Hope this helps! :)

I think its a pretty good plan. Since you are not in love with art museums, another option might be to stay in Segovia two nights and day trip to Avila, Salamanca. I'm guessing/hoping acraven would advise whether this is an option in terms of train routes. I have not been to Avila. It looks amazing, but from everything I've heard, It's about a 1-2 hr stop. I would also consider staying in Toledo a couple of nights. Barcelona is fantastic, 4 days given your day trip plans seems very short. Depending on the climate you are used to, Cadaques could be nice for you during your time frame. It is my understand that it can be cold/snowy at Montserrat, but I was there in January and it was lovely (for us midwesterners) I'd say the high that day at the top of Montserrat was 55 degrees and sunny. This was perfect for us for hiking. Another really charming spot within an hour commute of Barcelona is Girona. It's a stunning, medieval walled city.