Suggestions for Scotland/Ireland Trip

[SeumasA]

Wherever you decide to go, plan on it taking a lot longer than you expect. Scotland does not have anything like our interstate freeway system. A fifty mile trip can take two to three hours, depending on the roads. Personally, with only four days I would stick close to Edinburgh. You could easily take two full days in Edinburgh, then if you want to see historic sites take a day trip to Sterling, Bannockburn and the Wallace Monument, and another day trip south to Melrose Abbey and Roslyn Chapel.
Just my $.02

Edited to add: please don't take my comment about travel time and the roads as a negative. Scotland has great roads, in excellent condition and good repair. They're just different from what you might see here in the States. Don't look at a map, see something fifty miles away and think to yourself, "We could just jump on the freeway and be there in 45 minutes or so". 90% of the time you'll be wrong.
Also, there are a couple other things to keep in mind if you're going to rent a car. First of all, rent the smallest car you can. If it's just you and the wife, something like a Ford Fiesta or VW Polo (the Golf's little brother) would be great. Generally, your auto insurance will not cover a rental car in a foreign country. The insurance offered by the rental agencies is extremely expensive--two or three times the rental fee itself. Talk to your local insurance agent before you leave and see if you can line something up. GPS rentals are also exorbitant. You'd be better off taking your own and downloading a set of UK maps. Even if you plan on using GPS, you'll want a quality set of maps that show the B roads and single tracks.
Finally, you'll be driving on the other side of the road. Always look RIGHT before pulling out.

[Jock Scot]

Not wishing to depress any future visitors to Scotland, but in three score years and ten , plus a tad, of fairly extensive travel around Scotland I still have not seen it all. Not even half, probably!

[denmcdough]

Wherever you decide to go, plan on it taking a lot longer than you expect. Scotland does not have anything like our interstate freeway system. A fifty mile trip can take two to three hours, depending on the roads. Personally, with only four days I would stick close to Edinburgh. You could easily take two full days in Edinburgh, then if you want to see historic sites take a day trip to Sterling, Bannockburn and the Wallace Monument, and another day trip south to Melrose Abbey and Roslyn Chapel.
Just my $.02

Edited to add: please don't take my comment about travel time and the roads as a negative. Scotland has great roads, in excellent condition and good repair. They're just different from what you might see here in the States. Don't look at a map, see something fifty miles away and think to yourself, "We could just jump on the freeway and be there in 45 minutes or so". 90% of the time you'll be wrong.
Also, there are a couple other things to keep in mind if you're going to rent a car. First of all, rent the smallest car you can. If it's just you and the wife, something like a Ford Fiesta or VW Polo (the Golf's little brother) would be great. Generally, your auto insurance will not cover a rental car in a foreign country. The insurance offered by the rental agencies is extremely expensive--two or three times the rental fee itself. Talk to your local insurance agent before you leave and see if you can line something up. GPS rentals are also exorbitant. You'd be better off taking your own and downloading a set of UK maps. Even if you plan on using GPS, you'll want a quality set of maps that show the B roads and single tracks.
Finally, you'll be driving on the other side of the road. Always look RIGHT before pulling out.

Thanks for the added information. I appreciate everyone's help.

As for insurance and GPS, they're all included in our package deal, set up by the travel agent. This trip is a self guided type of deal with only lodging set in the bigger cities. The rest are B&B's.

[Kiltedjohn]

You have so little time, and everyone is bound to suggest their personal favourites!

One thing I would suggest is that, if you are going through Piltochry, make a detour to take in Loch Tummel and Loch Rannoch (on the "Road to the "Isles"). Great scenery, including the "Queen's View" over Loch Tummel, where Queen Victoria ordered her coach to stop so that she could take in the magnificent view.

[Carlo]

Back in 2010 I spent my holidays traveling from Switzerland to Scotland by car (Mitsubishi Colt). So I did not hire a car and have no experience with a car with british steering.

You'd be better off taking your own and downloading a set of UK maps. Even if you plan on using GPS, you'll want a quality set of maps that show the B roads and single tracks.
Finally, you'll be driving on the other side of the road. Always look RIGHT before pulling out.

Obviously you should have a map. You can buy great maps for little money in many shops and I would hope that a road atlas will be provided with a hire car.
We used a TomTom on our travel and we were quite happy with it. It knew all the little roads (we actually used those all along the west coast). I never before used a gps device because I can read maps, but I think it is a great help if you know where the road leads after the next turn especially when you're driving on the unusual left.

Car hire:
I don't know if it is possible, but I would advice to try and hire a car with the steering on the side you are used to. That way you would only have to adapt to the other side of the road. Driving on the other side of the road doesn't take long to get used to.

Oh and if you should decide to visit Skye don't think you can use your mobile phone. Didn't work for us, not even in Portree (we used a UK sim-card). It's not a problem if you book accomodation in advance, but if you don't you might spend a bob or two.

Obviously it is sad that you only have so little time. I think you have to make some decisions.
Are there places you NEED to see?
If yes plan your trip around those places. If you have to drive a lot, so be it.
If yes but they are all in/around Edinburgh, spend more time there and maybe a daytrip to the borders or/and Stirling as advised.
If no, Edinburgh for one day and then drive to Skye and then to Inverness (routes have been mentioned). I really enjoyed the driving and I saw a lot of the nature around me. Use the small roads and let others pass if they are faster.

I hope that helps and isn't to confused .
The one short point would be:
You can't go wrong with holidays in Scotland, no matter where you go.

[seanachie]

Den:
Everyone here is giving you tremendous advice for Scotland, but don't forget the Irish portion of your trip. I have spent considerable time in Ireland as I still have family there and used to own a flat in Ennis. If you have never been to Dublin there is plenty to see, but recognizing my prejudice, there is nothing like the west of Ireland. Connemara is one of my favorite places on earth, Galway is a fun stay full of good craic, the Aran Islands, Dingle and the peninsula, Donegal, Croagh Patrick and the list goes on..... Just do some planning for Ireland as well.