Spend two nights in Sintra, one in Óbidos and one in Nazaré, starting and ending around Lisbon. The first afternoon belongs to Quinta da Regaleira; day two gives Pena Palace and its park room to breathe. On day three, return by train to Lisbon to collect a car, then head north through Ericeira to Óbidos. The airport pickup keeps the Sintra stay car-free and gives a clear return point at the end of the circuit. The final night in Nazaré leaves an afternoon and morning for Sítio and the Praia do Norte headland. October–March is the appropriate season when the main aim is a chance to watch big waves, although a fixed five-day trip cannot guarantee a major swell. There is plenty to see if the sea is quiet: the fort, fishing town, bookshops, palace rooms and gardens give the route its substance. Keep outdoor sightseeing within daylight and use the car for the northern towns.