Frank's friend says:

a) spending some time in Edinburgh,

- definitly a must, especially the area around the caste, old town and new town.

b) visiting & walking in Glen Coe,

on the way up from Edinburgh to Glen Coe you will pass Killin (between Calendar and Crainlarich, head for the Falls of Dochart). In Killin you will find an excellent guest house named Invertay House, maintained by Gillean and Bruce Ford. Excellent accomodation with good breakfast and excellent evening meal. Highly recommended. Also a good place for starting some trips maybe to Ben Lawyers and some beautiful Glens around. Bruce and Gillean really know the area and they can give good advise for your trips.

c) touring and walking on the Isle of Skye,

also one of my recommendations. Stay in Portree, some nice guest houses and B&B's there, go for the tourist information, they are very helpful in finding accomodation, even if there accent is quite strange. Be aware that prices for accomodation on the islands are more expensive than on mainland (up to 30%).

d) touring and walking in the Torridon region

e) visiting the northwest corner of Scotland (Cape Wrath & Durness).

both a must. My recommendation is, going up the mainland to Ullapool and maybe further north. Back to Ullapool and take the ferry to the Outer Hebrides (Lewis and Harris). Some island hopping to the south and end up on Skye. If you take the bridge back from Skye to the mainland you will pass the Eileen Donan Castle. You will know it from the movie "Highlander (Part I)".

You also may take the ferry from Skye to Oban, which is a nice route. From Oban heading south the coast to the Isle of Jura and Isle of Islay. By the way Oban and Crainlarich are quite boring, nothing special. On the islands you will find some destilleries (Talisker on Skye e.g. or on Islay). In Pitlochry you will find Scotlands smallest destillery (The Edradour) but that's not directly on the recommended ways (east of Killin).