I have been to Scotland 3 times now. Once with the Clan Blair Tour in 2002.
To learn more about the Blair Estate (Blair House, Dalry, Ayrshire), go to
http://www.blairestate.com. Be sure to call ahead to inquire about a possible tour (not a public place) or any events that may be occurring.
When we toured the Rob Roy country (around Crieff) we encountered what they call 'miggies'. Fierce and relentless. But, it didn't deter us from seeing the countryside.
Some of my favorites were the quaint little port of PortPatrick (extreme SW coast) where the ancient Blair Castle ruins are just a short walk. It is a day trip, but I also tied in visiting the Robbie Burns homestead near Ayr and PortPatrick was just a nice visit. Another was the ferry from Oban to the Isle of Mull, where we spent a night in Tobermory. Then, another ferry the next day to Iona. We stopped at Inverary Castle (home of the Campbells) on the way back to Greenock.
Other Blair related places where we've visited or stopped were Blairgowrie (ArdBlair Castle is just outside of Blairgowrie), which is a short distance from Blair Castle (not a Blair property) which is well worth seeing. South to Perth, Balthayock is a short ways away. Remember, though that most of these Blair properties are privately owned residences and it is best to attempt to contact the owners before attempting to visit. It's like someone just knocking on your door, that you don't know, and asking for a tour.
If you visit Blair Castle, the Blair Atholl Distillery is in Pitlochry. This is where we buy our personal stashes of Blair Atholl whiskey.

Pitlochry is another nice little town for shopping or a break.
I could probably go on for a while about the Blair properties and sites in Scotland, and I haven't even touched a fraction of them. I'd suggest laying out a plan to visit those places that are really important to you, then add sites and locations as your schedule allows. Be sure not to burn yourself out trying to get to too much. Scotland isn't going anywhere.
Good luck, and have a great trip!