For castles, right in Edinburgh is of course a castle, well worth the tour, see the Scottish crown regalia and the Stone of Scone. Another worthwhile trip, accessible by train, would be Sterling Castle, another historically important sight.
For Whisky/Whiskey (The difference is purely spelling, like Color/Colour, Center/Centre, Defense/Defence), unfortunately most distilleries require a car and are located away from Edinburgh and Glasgow, up into the highlands or the islands. But do some searches for both cities. There are certainly lots of shops offering tastings and education. Edinburgh also has places like "The Scotch Whisky Experience", "The Edinburgh Whisky Trail", and the "Johnnie Walker Experience", bigger flashier, maybe interesting, maybe a bit too touristy, but maybe worth it.