How many days?

My side hustle is interviewing internationally renowned orthopedic surgeons since 2023. I am going to Europe in July as a business trip to do 13 in person media 2 hour interviews. I have people in Helsinki, Copenhagen, Munich, Innsbruck, Madrid, Barcelona, 3 people in France and 3 people in London.

My aunt lives in England, so we’re having dinner together. When I get over there, I will travel with 2 friends and having dinner with other friends along the way.

How many days should this trip be?