Hello! That sounds like an exciting trip to some of Portugal's most beautiful coastal towns - Setúbal, Costa Da Caparica, and Cascais. Here are some detailed tips to help you plan your journey.

Best Time to Visit:
The best time to visit these coastal towns in Portugal is from late spring to early fall, specifically from April to October. During these months, you'll find pleasant weather ideal for the beach, sightseeing, and outdoor activities.

Route and Accessibility:
Start your journey from Lisbon, the capital of Portugal. Setúbal is about 48 km south of Lisbon, easily accessible by car, bus, or train. From Setúbal, you can reach Costa Da Caparica by crossing the Tagus River by ferry, then driving or taking a bus. Cascais is situated west of Lisbon and can be reached via a scenic train ride along the coastline.

Accommodation and Booking:
These towns offer a range of accommodation options, from luxury hotels to more budget-friendly guest houses and apartments. It's advisable to make your bookings in advance, particularly if you will be traveling during the peak season.

Clothing and Essentials:
Be sure to pack light, summer clothing for the beach as well as a light jacket or sweater for cooler evenings. Don't forget sunscreen, sunglasses, a hat, and a swimsuit. A pair of comfortable sandals or walking shoes would be ideal for exploring the towns.

Health and Safety:
Always stay hydrated as the weather can get quite hot, especially during summer. Pay attention to traffic rules if you're renting a car. Don't forget to keep your travel insurance handy, and familiarize yourself with the location of nearby medical facilities for emergencies.

Local Etiquette and Respect:
Portuguese people are generally very friendly and polite. If you learn some basic Portuguese phrases and use them when interacting with locals, it will be very appreciated. Remember to respect the local environment, especially on the beaches and in natural areas.