Cascais sits at the western tip of the Lisbon coast and makes a comfortable base for the surrounding region. Sintra, half an hour inland, is the obvious major trip — the cool wooded hills, the Pena Palace, the Moorish castle, and the gardens of Monserrate make a full day. The summer royal court used to move from Cascais up to Sintra in July, and the rail and bus links between the two are easy.
Lisbon is 40 minutes east by train, and a Cascais base can pair well with a long day in the capital — particularly Belém and the river-front districts, which the train passes through. The neighbouring resort of Estoril is so close it almost merges with Cascais: famous for its grand casino, the long seafront promenade, and several handsome villas built by European royals in exile during the wars of the twentieth century.