Continued thanks for all the good ideas and information!
I've already booked a car. I'll get into Glasgow before lunch. I plan to see a few things in Glasgow then make a leisurely drive to Edinburgh. I have a hotel in Edinburgh, kind of between downtown and the airport in Edinburgh (I fly out there the next day, so I don't have to go back to Glasgow). The hotel has free parking.
If I go up near Loch Lomond, maybe go to Stirling Castle, then go through the countryside to Edinburgh, I should be out of the way of the heavy traffic? Of course it will still take a while since I'd be going the long way, but at least I'd be seeing the sights. Someone mentioned Balloch on Loch Lomond, maybe I'll head there. In Edin-bruh I'll probably walk the 'Royal Mile.'
Since I'm an American and you guys drive on the wron... opposite side of the road as us, I got the most rental car protection I could.
Holyrood Park/Arthur's Seat hill is in my plans, around sunset. Hopefully I can drive my car near there.
P.S. Great landscape pictures Paul