Hello! It's wonderful to hear that you're planning a trip to Monsanto, Óbidos, Marvão, and Sortelha in Portugal. Let me provide you with some helpful travel tips.

Best Time to Visit:
The best time to visit these towns in Portugal is between March to June or September to November when the weather is still warm but not as hot as in the peak summer months. However, each season offers unique beauty.

Route and Accessibility:
There are several airports in Portugal, with Lisboa and Porto being the major ones. From the airports, you can rent a car or use public transportation like buses or trains. The towns are well-connected to each other, but do remember that some are located on hilltops, so be prepared for some hiking.

Accommodation and Booking:
You'll find a mix of accommodations ranging from luxury hotels to local guesthouses in these towns. As they can be quite popular, especially during the peak tourist season, it is advisable to book your accommodation well in advance. Websites like Booking.com or Airbnb can be useful.

Clothing and Essentials:
Given the terrain and weather, comfortable footwear is a must, especially for the cobbled paths and steep inclines. A water bottle, sun protection, and a lightweight rain jacket are also recommended. Don't forget a camera to capture the stunning views!

Health and Safety:
Portugal is generally safe, but always have travel insurance in case of emergencies. While hiking in the hills, be careful of loose rocks. Also, ensure you are up-to-date on routine vaccines before your trip.

Local Etiquette and Respect:
Portuguese people are warm and welcoming. Dress appropriately, respect religious sites, and try to learn a few basic phrases in Portuguese. The preservation of these historical towns is a point of pride for locals, so avoid littering and take care of the environment.