We did 8 nights total last year (3 in Callander, 3 in Skye, 2 near Loch Ness) so maybe some of that will fit. Have a look.

http://www.fodors.com/community/europe/scotland-trossachs-skye-and-loch-ness-an-indydad-trip-report.cfm

Others (janisj) can help more with the logistics and suggestions.

It's a long drive from St Andrews to Skye, at least 5 hours not including any stops or delays due to roadworks/slow-moving vehicles etc. Scotland's geography and rural infrastructure just isn't designed for moving from one side of the country to the other in a hurry. If getting to Skye is essential - and believe me it doesn't have a monopoly on amazingly photogenic scenery (and certainly not castles) - I'd re-organise the trip to include 1-night stopovers on the way there and back and spend less time in Edinburgh.

"We want to head out to the Isle of Skye and have that day and the next 2 nights before we head back to Edinburgh for 3 days."

Sorry -but that just doesn't make sense. As Gordon says - Skye isn't the only scenic part of Scotland . . . By a LONG shot.

Since St Andrews is a must and the basis of your trip -forget about crossing all of the country just to glimpse Skye. Stay on the east coast -- plenty of castles and scenery.

As an example - Nothing like this on Skye . . .

http://tinyurl.com/a32gpzh Dunnottar Castle up the coast from St Andrews.

or Castle Campbell http://www.historic-scotland.gov.uk/propertyresults/propertyabout.htm?PropID=PL_058&PropName=Castle%20Campbell%20And%20Garden

Falkland Palace/garden http://www.nts.org.uk/Property/Falkland-Palace-Garden/

Glamis Castle http://www.glamis-castle.co.uk/

. . . And Gordon_R's 5 hour drive estimate is pretty optimistic. The fastest route from St Andrews to say Portree (and missing Glencoe) will easily take 6 hours w/o a single stop.

It's only about 80 miles from St Andrews to Aberdeen, which means Aberdeenshire, which means castles and castles and castles and more.

See here: www.aberdeen-grampian.com/

Thanks everyone. Great input. Perhaps Sky should be left to the next trip to visit our daughter when Edinburgh will no longer be on the itinerary!

Since we may be changing tactics...any recommendations for where to stay the 2 nights between St Andrews and Edinburgh? Wondering which town/cities would work best as a base.

Also, any good tour routes? I like the idea of Glamis and Dunnottar.

If it was me, I'd stay somewhere north - probably along the Dee. Banchory, Ballater, Aboyne, thereabouts. Visit Glamis and Dunnottar on your drive north the day you leave St Andrews. Then during the 1.5 or 2 days you'll net up in Aberdeenshire you can see lovely river/mountain scenery and as many castles as you want (the area is called 'The Castle Trail'). Crathes - wonderful castle w/ gorgeous gardens. Craigievar, Fraser, 10+ others.

Then go west along the A93 and down the dramatic Spittal of Glenshee and on to Edinburgh. From Braemar to Edinburgh airport (the best place to drop off the rental car) tales about 2.5 hours and is pretty much a straight shot. A93 to Perth/M90 to EDI.