Scottish Roads!

Hi. I am planning a trip to Scotland this year and would appreciate some advice on the route to take. I am planning on staying at the CC site just south of Fort William which means taking either the A82 from Dumbarton or the A84 from Dunblane. I have been told that the A82, particularly past Loch Lomond, is really tight in places especially when towing a van and is a nightmare with oncoming traffic, especially large lorries etc. Could you please advise on the best route and any other helpful suggestions would be much appreciated. Many Thanks.