Glasgow to Oban

Visit Easdale. Take a small ferry to the island.

http://www.easdale.org/

First of all, I hope you will not be driving while jetlagged. The roads are not the easiest, and you say you don't want to rush, but it is a fairly long drive so you will not have time to stop and do very many things.

If you have time and the weather is favorable, you could take one of the Loch Lomond cruises out of either Balloch or Luss. I think the shortest cruise is about 1.5 hours, though. That amount of time might put you behind schedule in getting to Oban.

Inveraray would be a logical place to have lunch. Brambles has excellent food. There are a few shops in town that specialize in Scottish woolens. Inveraray Castle has beautiful gardens, and I found the interior to be stunning (au contraire to the RS guide). It has a small cafeteria and a nice gift shop, and we loved watching the herd of black sheep in their pasture right outside the car park. We enjoyed Inveraray so much on our first trip that we made a point of returning the following year.

Heading out of Inveraray toward Oban on the A819 you'll pass the photogenic ruin of Kilchurn Castle (best photographed from across the loch) and then, in the village of Lochawe, the fascinating visitor centre for Ben Cruachan "Hollow Mountain" hydropower plant. It sounds nerdy but it's really excellent. You probably won't have time to take the tour inside the mountain, but a walk through the visitor centre would give you a nice chance to stretch your legs.

The drive along the A85 approaching the Connel bridge is pretty spectacular.

Thank you ramblin’ on.
epltd, thank you as well. No driving until about day five:-)

I drove from Glasgow to Oban in August 2016 (right after getting off a plane). However, I decided to stay one night in a tiny town called Kilmartin. It's not the direct way to Oban from Glasgow, but decided I wanted to go there because of a museum that is in that town and some standing stones located there (plus a lot of ancient history of Scotland). There was a little BnB I stayed at and drove into Oban the next morning (about 1 hour) to catch the ferry to Mull. The drive to Kilmartin was scenic and I was blessed with lovely weather. I think it was probably about 2 hours or so to Kilmartin from Glasgow airport. If you are an Outlander fan or just interested in ancient Scottish history - then I highly recommend stopping in Kilmartin. You take a short hike to the standing stones and I walked right up to them. Here's a video about them: https://www.youtube.com/watch?v=79XoFGlexVY . I'm so happy I did this - I have some of the best pictures from that day!

Yes, I agree about Kilmartin, though it is on the more southwesterly route to Oban than the one that goes through Lochawe / Ben Cruachan. Our trip had been focused on stone circles and by the time we got to Scotland my dear husband was refusing to go to yet another stone circle, but I convinced him to ride along to Kilmartin (from Inveraray, where we were staying). The countryside is very scenic, and he found himself very captivated by the carved stone slabs in the churchyard, as well as just chatting with the locals. It is well worth stopping in the tiny Kilmartin museum to buy the map to the cairns, as they are not well signposted and you can easily drive right past the turnoff if you don't refer to the map.