Actually, the Bealach is scarier for the driver on the way west. There are a couple of videos on YouTube, which I'm sure you've seen. This one's pretty good, if you haven't seen it yet: www.youtube.com/watch?v=34aH2QUYGUE I have a good friend in Aberdeen who used to drive a bread van up the Bealach to Applecross once a week. And that was before they built the coast road, so the only way to get back to the A896 was to go back over the Bealach.
Where you go from the Northwest on your way back to Edinburgh depends a lot on how much time you have left. and how much driving you feel comfortable doing in a day. You definitely wouldn't have enough time to get to Orkney. You have a couple of options which may work for you - you could take the A9 south from Inverness, and visit some of the towns along the way to Edinburgh. Aviemore, Pitlochry, Dunkeld, and Stirling, for example, with possible side trips to Loch Tay, Killiecrankie, Crieff, or Dunblane.
Another option, if you have the time, would be to visit some of the towns and fishing villages along the Moray coast. Nairn, Forres, Lossiemouth, Findhorn, Spey Bay, Portsoy, Banff, Macduff and Buckie are all great places to spend some time, as well as Elgin, with its cathedral. You could then head down toward Aberdeen, take the A90 bypass, and visit Dunnottar Castle, south of Stonehaven, before heading down the East Coast to Edinburgh.
I know it's last minute, but try to find one of the comprehensive guides to Scotland, like the Lonely Planet or Rough Guide. You'll probably get some good ideas there.
Whatever you decide to do, you're going to be travelling through some of the most beautiful scenery in the world. Enjoy every moment!