✔ 最佳答案
According to your schedule in question
http://hk.knowledge.yahoo.com/question/?qid=7007082905431. You will travel by trains on 6 days, but since the Eurostar bewteen Paris and London is not counted in the train pass, so you don't need to calculate this journey. So you only need a 5-day pass if you really want to buy it. Train pass normally is valid on trains between cities. For transport in cities, e.g. metro, bus, tram etc., it is not included, you need to buy other tickets
For this questions, you need to calculate the price of each single ticket. Although you paid 204 euro to get a train pass, you still need to pay resevation fee if you ride on a night train or express train. Usually, it will be the same if you only travel in Italy. But If you go to Paris from Milan by train, then a railpass will help you. As this journey cost you more than 100 euro if you buy single ticket.
It really depends on your choice... Malpensa and Charles de Gaulles is the main airport of Milan and Paris. Linate and Orly is for local or short internation flight. So if you ask me, I will hvae no preference. You should focus on the time of departure and arrival of flights, but not the airports... Malpensa and Linate, and CDG and Orly, their distance to city centre is similar