This was the perfect location in Cascais, right next to the very large and convenient Jumbo supermarket and a few minutes walk to the beaches, shops and restaurants. We also took the train to Lisbon, which was less than 10 minutes away walking. The apartment was very spacious, clean and comfortable and could easily fit 4 guests with the pullout sofa. The only suggestion is to use a cellphone light in the hallway at night and take a picture of your door/apartment number as it can get confusing at night.
Restaurants:
Our first night we had dinner at a great Indian restaurant called the Taj Majal and lunch the next day by the water (don't remember the name but it's an ocean view restaurant that is above a beach with benches facing the ocean near shops).
Transportation:
Walking everywhere was pretty easy but wear sneakers as the stone paths are slippery and steep.
Shopping:
Jumbo supermarket is like a Walmart/Target and they have everything from food, electronics and clothing to restaurants inside. Highly recommend dor last minute items and they're open late.