Spain and Portugal

Allow 1/2 day for traveling each time you change locations, and a whole day from Spain to Portugal (are you flying?).

Probably 4 days in Barcelona, maybe one more since it's your first stop, to get over the jetlag, etc. There's 2-3 days of sightseeing in Madrid itself, but there are day trips to other places. . . Segovia, Toledo, Avila. Sorry, don't know about Valencia or Lisbon.

Thank you so much. Will look at the day trips as well.
Pan

Pan, the previous poster raises several good points - there are significant distances involved with your itinerary, especially getting to Lisbon. You'll receive better assistance if you specify your mode of transist. One of my travel principles - less can be MORE - would encourage you reduce destinations or distances in order to see more sights will transporting yourselves less. Madrid, is an excellent base for smaller delights in Toledo, Segovia, etc. (an easy drive, bus or tour bus from Madrid); Girona is a nice day trip from Barcelona or the nearby Dali sights (Figueres & Pubol); from Lisbon I'd recommend with a day or two in Sintra. While I'm far from a destination expert (two trips to Spain and one to Portugal), I try to organize all of my itineraries to avoid trying to cover too many sights in a limited # of days, and to mix smaller destinations with the big cities (full disclosure - I rent a car and drive from destination to destination and therefore keep the distances within 2 or 3 hours everyother day). Driving is not for everyone but I've really enjoyed the flexibility. For example, near Madrid we visited Toledo, Segovia, Salmanca and Avila. When in Barcelona, we saw Girona, Figueres, Pubol, Pals and Cadaques. Portugal was a separate trip to Lisbon, Nazarre, Coimbra, Porto, Duoro and Evora.
You may want to consider dropping Valencia for more time in the other destinations; or, try looking into a Spain only trip and add Granda (versus Valencia).

Have a great trip.

My advice... reduce your base camps to three: Barcelona, Madrid and Lisboa. You can visit Valencia on a day trip from Barcelona or from Madrid... from the later via a fast speed train you're in Valencia less than 2h, having several trains per days starting at 7am. Given your tight schedule, my approach would be: Barcelona (5-6 days), then fast train to Madrid (4-5 days) and then flight to Lisbon, then include some day escapades from each base camp. These escapades can be done with regional public transportation (bus/train) so there's no need to hire any car.

The three cities are historical, cultural and vibrant enough to require much more time for each one, even more if you want to really visit their regions -and trust me, there are lots to see and do- but given your limited time, the above would be my best advice. You'll be able to have a taste of them with the allocated time.

Travel time: I don't quite agree in that travelling from one base camp to the next will take you so much time. In fact, from the centre of Barcelona to the centre of Madrid via fast train travel time is approx 3 hours and trains depart from 6am. Then, flights MAD-LIS take 80' and if you must return to Barcelona for your outgoing flight home, a LIS-BCN flight takes around 2 hours. Different low cost companies serve these lines, among which Easyjet and Vueling.

For info:
www.renfe.com -train operator (for fast trains and for regional trains outside Catalonia)
www.rodalies.tk -train schedules for day escapades within the region of Catalonia

Craig and Enric wrote before I could!!! They give great advice. Less is more!!!!

Actually it is quite doable, though getting to Lisbon is the key as it is not well connected to Madrid (just one overnight train). Hopefully you have planned to fly.

Four nights in Barcelona will get you all the highlights. 1-2 nights in Valencia (there is WAY too much to do there for a daytrip). Four nights in Madrid and four nights in Lisbon. That might give you an extra day to tack on somewhere of your choosing.

All three major cities have excellent daytrip options. With four nights you can get at least one daytrip each. Or spend the entire time just in the city. Daytrips can be great, as is staying longer in a city and using it as a base. But don't feel obligated to travel that way.

I don't quite agree in that travelling from one base camp to the next will take you so much time.

Chani's 1/2 day block for traveling between each city is just right. It isn't just the transit time, you have to tack on checking out of your hotel, getting to the station, getting to your new hotel and settling in.