Callander, Mallaig and Skara Brae (which I thought was IN THE WATER south of Orkney Mainland - something with the German submarines in WWII) should be correct - the other names I'm not sure of.

Scottish Explorer is something (afaik) the Scottish Heritage gives out. With those passes you always should check which sites are included and which you want to visit.

In Britain some sightseeing sites (castles, gardens and so on) belong to the National Trust (in Scotland National Trust of Scotland) or the English Heritage (in Scotland Scottish Heritage). You can either buy something like this Explorer from one organisation (which gives you free entrance only for sites of THIS organisation) - or you become a member of that organisation for a year at least (same effect only longer) - or you buy that Great British Heritage Pass which includes many sites from DIFFERENT organisations (for two or four weeks). It all depends what and how much you want to see in which period of time.

hth Baerbel.