Personally, I would skip Oban. In my view the real value of Oban is that it takes you to Mull and other islands. I would head north. And if you are willing to be flexible in your lodging then pay attention to the weather. Watch where the rain is.
If you just drive straight to Fort William from Glasgow--A82 north--Via Michelin says 2.5 hours. So, you would probably do it in 3 to 3.5 hours--you will stop for pictures! This route takes you through Glencoe and over Rannoch Moore. The Road to the Isles isn't really drivable. It starts in the East near Queen's View and Loch Tummel, and Loch Rannoch, which is where the current road ends. You basically can't cross Rannoch Moor. You will see Rannoch Moore on the A82 as you head into Glencoe. You will probably also want to stop and visit the visitor's center for Glencoe and see some the water falls on your way through the Glen. If you want to take the ferry to Skye from Mallaig, you could continue west on the A830. It's a beautiful drive. You pass the Glenn Finnan Monument (where Prince Charlie landed) at Loch Schiel and you'll see the Harry Potter viaduct. You could probably find an interesting B&B along the way.
It's a wonderful drive from Skye to Applecross. It really is stunning. Bear in mind that Skye is bigger than you think. For example it's a little over two hours to drive from Portree to Applecross, but an hour of that trip is on Skye! You drive over the bridge to Kyle of Lochalsh and take the A87 west past Eilean Donan. You head north on the A890 north to Loch Carron. Then head west again on the A896. This is a stunning drive. You take a wee road west to Applecross. This road is even more stunning. BTW there is a nice place for lunch in Applecross--The Potting Shed. You can continue north and the road does wind around to the A896. Go north and it will take you through Glen Torridon. You could go west to Gairloch and stay there or stay near Kinlochewe.
Take the A832 east to where it joins the A835 (check out the waterfalls.) You have a couple of choices. You could continue east to Inverness. Another alternative would be to take a side trip to Ullapool. There are some lovely walks in the hills with marvelous views of Loch Broome.