Arrive mid-morning on Edinburgh, settle in, plan a light day with outside time to recover from jetlag. 3 full days/4 nights in Edinburgh,
Drive Edinburgh to Dundee (110 miles), visiting Jupiter Artland, Linlithglow Palace, Falkirk Wheel, Culross Palace.
4/5 nights days in Dundee: a couple of days for sights in town, one day to visit St Andrews (30 miles), one day for a castle/palace loop of Falkland, Scone, and Glamis ; the J.M. Barrie BIrthplace only if time permits (95 miles).
Drive Dundee to Aberdeen, visiting the House of Dun, William Lamb Studio (if it's one of the rare times it's open), Dunnottar Castle (80 miles).
3 nights/2+ days in Aberdeen, one day for sights in town, one for another castle loop: Crathes, Craigievar, Fraser, Fyvie (only if time, it adds 50 miles; 66 miles without Fyvie).
Take 5pm-11pm ferry Aberdeen to Kirkwall, Orkney Islands.
3 days/4 nights on Orney.
Ferry Stromness to Scabster (90 minutes), drive 195 miles via North Coast 500 to Gairloch. Since it's a long drive, no sightseeing stops planned--maybe just photo ops.
2 days/3 nights Gairloch, one day for the Heritage Museum, Russian Arctic Convoy Museum, Inverewe Gardens, one day for Glen Torridon, Loch Maree, Beinn Eighe.
Drive to Portree, visiting Eilean Donan Castle, Glenelg ferry to Kylerhea (120 miles plus ferry).
3 nights/2.5 days on Isle of Skye.

Whew! That's as far as I've gotten.
Working backwards, we'll end in Glasgow (?2/3 days?), and before that, 3 nights in Selkirk or Galashiels to see the sights in that area.
Of course, I still need to plan for the Cairngorms NP area, Loch Lomond & the Trossachs, and the South.
If my math is right, considering my rough count for Glasgow & the Borders, I have 14-15 more days to play with.
I welcome your comments on what I've (tentatively) put together so far and suggestions for the time between Skye and the Borders.
Many thanks!

>>4/5 nights days in Dundee<<

I would not stay in Dundee at all - a couple of nice museums but not a place I'd stay. I'd stay in St Andrews or one of the Fife fishing villages.

Your drive to Dundee doesn't make sense. That is nearly a 4 hour drive plus four major stops.

>>one day for a castle/palace loop of Falkland, Scone, and Glamis<<.

Not really an easily doable day trip. -- Nearly three hours car time plus thee MAJOR stops.

I haven't yet read the rest of your plan but suspect you are trying to cram WAY too much into too little time -- and trying to do this for 6 straight weeks will be crazy making . . .

Will try to absorb the rest of your post after dinner, but I'm not optimistic.

ps: You really need to add to your drive time calculations.

I always include a lot in our daily itinerary, knowing that we can drop things as we go. For us that's preferable to scheduling light days and ending up with dead time where we don't know what to do.

I chose Dundee because there's a lot to do in town as well as having several places within a reasonable drive. We find that it's easier to find lodging we like and having plenty of restaurant options in larger cities.

I definitely consider everyone's opinions, factoring in what I know about how we like to travel.

Thank you.

Oh, darn--I forgot to say that I didn't include any drive times, just mileage.

>>Oh, darn--I forgot to say that I didn't include any drive times, just mileage.<<

I know you didn't -- but it seems obvious you aren't allowing enough time for your various days.

IMO Dundee is an excursion FROM somewhere , not a destination. But YRMV . . .

I honestly think I can't be of much help to you - from your other thread it does seem you have some preconceived ideas what is doable. But it IS your trip . . .

janisj, I value all suggestions and give them very serious consideration--even when I don't immediately change my plans to fit those suggestions.

In fact, I reviewed my notes about things to do in both St Andrews and Dundee to make sure I was clear about how much time we would enjoy in each place. I re-did the driving loop from St Andrews to see how that would work--but adding more mileage when you tell me I'm already doing too much didn't make sense. Maybe there's something I'm just not getting.