Q3- The nature of the geography and the distances mean that significant travel times on any Scottish itinerary which starts in Edinburgh and then concentrates on the west coast are an inevitability.
Q5- Pitlochry is touristy because for the most part it was built as a tourist town, with the coming of the railway, then the primary means of transport to the area (even for the Lairds). But as in many other such places it is incredibly easy to escape fellow tourists.
The more historical part of Pitlochry is a village less than 2 miles up the hill called Moulin. The village has a well respected hotel. When I go up there I know I am leaving all the tourists behind as soon as I start up the hill. Pitlochry Heritage Centre is actually in the former Moulin Church (Kirk).
But a nearby town with a lot more Scottish History, but way fewer tourists is Dunkeld (and it's sister village of Birnam).
From Pitlochry you could also look at heading out west towards Rannoch- lovely but little known (to overseas tourists) countryside.
Q6- Getting from Edinburgh to Islay by road is basically going round two sides of a triangle. In my mind the far better way to get there by road is to take the base of the triangle- the 2 or 3 ferry route- either Western Ferries Gourock to Dunoon then CalMac Portavadie to Tarbert (Loch Fyne); or Wemyss Bay to Rothesay, then Rhubodach to Colintraive, then Portavadie to Tarbert.
It is no faster, but is just in every way better in my opinion.
The time saving way to get there is to fly from Glasgow to Islay (morning and afternoon flights). On a good day the little flights are a good sightseeing opportunity, as a side benefit. Until you've seen the islands by air I don't think you truly grasp the geography of the west coast.
Tarbert (Loch Fyne) is a possible small town to use as a base to explore Kintyre. Campbeltown (at the bottom of Kintyre) is a whisky region of it's own, and has several (3 or 4) distilleries you can visit. The Isle of Gigha (half way down Kintyre) is an easy day trip, and a good example of a community buy out island (from it's former Lairds) with several good community businesses. Another little town I like a lot on the way across Cowal to Portavadie is Tighnabruaich- a one or two nighter.
Please bear in mind that drink driving laws in Scotland are strict, driving and drinking any measure of whisky are mutually exclusive actions. There are several island companies on Islay who will do private distillery tours for you. I also think you will find the whisky contrast between Islay and Jura (it's neighbouring island, quick ferry hop over) rather interesting.
Islay has two island car rental companies, and a pretty comprehensive bus service, mainly (it seems) by the locals. Islay is a big island with a lot of scenery and places to explore outwith the distilleries. Including travel days then you could readily make Islay cover the whole 5 or 6 days at your disposal.
The time saving way from Islay to Oban for Tobermory is the twice weekly direct ferry from Port Askaig to Oban. I have to say that the thought of Oban being too big is a bit thought provoking. The tourist part (as opposed to where the locals live) is little more than two long streets. Yes it's busy because it is a major port. But again it takes little effort to escape fellow tourists- even in the town itself (go up to McCaig's Tower or Dunollie or Dunstaffnage , or going across to the islands of Kerrera or Lismore on the wee ferries.
Lismore in particular has the nice island cafe in the Gaelic Heritage Centre.
