Thank you Sheila. That is the kind of info I was looking for!
What do you think about taking the route from Perth to Pitlochry and up to A86 west to Ft. Williams and then to Lochaline?
Then, on the way back to Edinburgh, taking the Corran Ferry and on to Ballachulish, Crianlarich, Callender, Stirling, etc. (not necessarily stopping points - just marking the route)?

Sheila: Even AA's route finder gives the most direct drive from St Andrews to Lochaline as 4 hrs 21 mins. And AA is known for being very optimistic. You really think a visitor will do it in anything like 4 hours??

IMHO, 5.5 hrs on a good day - minimum.

mccarder: I've been to all the places sheila mentions and any/all of them would be great places to stop. All are pretty much ON your route except Killin (probably the prettiest of all) which would add at least 35-40 minutes to your route (w/ the R-T in and back out).

And Lochaline to Dervaig will take you 90 minutes minimum.

Don't (really, don't) underestimate the distances involved - remember, Sheila lives there and can take those single track roads in stride -- maybe she'll volunteer to be your driver

Just plan on being on the road (including stops) for at least 8 hours -- and 9 or 10 wouldn't surprise me unless everyone is on the same 'schedule'

Sorry; my bad. I did, indeed mean Loch Linnhe.

I think the A96, Loch Laggan route is seriously boring by comparison with teh direct route.

If you want to ring the changes on the way back come off to Oban, then go back to Edinburgh via Inverary and round Loch Lomond. Further, but fun.

My time estimates are my own, but I note Via Michelin agrees with me