We are planning a three week trip to Scotland in October. We are thinking about taking day trips on trains from Edinburgh to St. Andrews, Inverness to Aviemore, and Glasgow to Fort William, for example, using the larger cities as bases and getting to the cities by train as well. No car. Looking for comments on how day trips like this by train have worked for someone out there. Also, is there an advantage other than possible lesser cost to using an 8 of 15 day pass?