I did a week in 2012.
Spent a couple of days in
Lisbon - historic centre, and the Aquarium (Oceanario) in the NE of town is good too! I can much recommend the
Britania Hotel. Its Art Deco, near some good restaurants and a brisk walk into the centre of town. Also has the charming aspect of having decanters of port spread about, including in one's room and at breakfast
. Castelo de Sao George gives great views over the city. Panteao Nacionale a good sight, and views as well; the Se, excavations of Roman buildings; view from Miradouro de Santa Luzia. I didn't do the Cable Car (SFO-like tram) but wish I did. Speaking of SFO, check the main bridge in town
I then drove north, stopping at
Peniche to see the sea side fort and to have sardines grilled over coals by the sea. Yum!
Then to nearby
Obidos - gorgeous old town and Roman aqueduct and crenulated town wall; whitewashed buildings with sky blue highlights; bougainvillea, the works.
Couple of days in
Porto and surrounds. Fascinating down-town and collection of bridges over the Duoro River. Took a tour of Taylor's Port Lodge. Sample different ports, tour of the cellars etc. Euro 7 I think - great value. Then drove up the Duoro inland to see where the port vineyards are - arid and hilly. Something came up and I lost half a day so didn't see much other than the sights from the highway. the Pousada (chain) there: Hotel Palacio Do Freixo is avoidable.
Headed further north and inland to
Guimaraes to see some historic buildings (stayed at the Pousada Old Monastery - recommended, but you need wheels).
Freeways are excellent (good 'ol EU cash!) but the next level down are slow. I found this out the hard way - I had intended to avoid the freeways, as you miss so much, but the 'highways' are just so slow!
I avoided the south of Portugal (Costa del Sol) as I figured it would be full of beer swilling Poms.
"Pousada" is a
chain of hotels based mostly in historic buildings such as old castles, monasteries etc in Portugal. Worth checking out but in my limited experience not a patch on the equivalent chain in Spain, the Paradores.
Edit: English isn't as well spoken as you might imagine in tourist spots, but you'll manage. I hired a car and would suggest that - as I mentioned, the freeways are good or you can always take the slower highways.