Hello and congratulations on planning your trip to Lisbon, Costa Da Caparica, Cascais, and Sintra. It's bound to be a fantastic trip with the right preparation.

Best Time to Visit:
The best time to visit these places in Portugal would be either during the spring months (March to June) or the autumn months (September to November). During these times, the weather is usually warm and pleasant, which can make sightseeing and other activities more enjoyable.

Route and Accessibility:
You can reach Lisbon via flight at Lisbon airport, which is well-connected internationally. From Lisbon, Costa Da Caparica, Cascais, and Sintra are easily accessible by train, bus or car. Frequent train service from Lisbon is available to both Cascais and Sintra, while Costa Da Caparica can be reached by bus or ferry from Lisbon.

Accommodation and Booking:
There are a variety of accommodation options available in these locations from boutique hotels, guest houses, to vacation rentals. These can be booked through popular online platforms such as Booking.com or Airbnb. Remember to book in advance, especially during the peak season to guarantee availability.

Clothing and Essentials:
Essential items to pack include versatile clothing suitable for warm days and cooler evenings, comfortable walking shoes for sightseeing, sunscreen, a sun hat, sunglasses, and a reusable water bottle. If you plan on visiting any religious sites, make sure to pack clothes that are respectful and cover your shoulders and knees.

Health and Safety:
While these areas are generally safe, always be mindful of your belongings, especially in crowded tourist areas. Standard vaccinations are recommended for travel to Portugal. You might consider a health insurance plan that includes international coverage. Also, pharmacies in Portugal are well equipped, but it's always a good idea to carry necessary medications.

Local Etiquette and Respect:
Portuguese people appreciate politeness and good manners. When meeting locals, a firm handshake with eye contact is the norm. If visiting a Portuguese home, a gift for the host in form of flowers, wine or chocolates is considered good practice. Respecting local customs and environmental etiquette, particularly at beaches and natural parks, is a must.