Portugal is small enough that a week can hold a city, a wine region and a stretch of coast without long drives. Lisbon and Porto are hilly, tiled cities made for walking. The Douro Valley has port wine estates on terraced slopes above the river, and the Alentejo has cork forests, whitewashed towns and the empty beaches around Comporta.
We pair Porto with the Douro, and Lisbon with Sintra, the Alentejo or the Algarve. Madeira and the Azores work as separate trips, for walking, gardens and whales rather than beaches.
The honest caveats are the Atlantic and August. The sea is cooler than the Mediterranean even in high summer, and the Algarve is at its busiest in August. The Douro can be very hot in July and August, so we prefer late May, June and the harvest in September.