Greetings Porto experts... We are based in Porto for 2 weeks, starting next week. After we enjoy Porto people and culture, we want to visit Aveiro, Braga, Douro Valley (by boat?), Guimaraes, and Viana do Castelo. And possible Vigo, Spain. We will book some guided tours, such as walking tours or special historical edifices. However, we prefer to use trains or buses as we are independent visitors, wanting to leisurely enjoy the wonders of Portugal. Please advise about user friendly sites for trains and buses. Thank you very much for you assistance. We are jazzed for this adventure!