Hi Maddock
There are many members on this site far more qualified than myself, but my advice would be to not try too much and go for quality rather than quantity. Instead of trying to ride right round Scotland in a rush, pick a spectacular area like the West Coast and Skye and take your time to soak up the fantastic views and roads.
If I only had three days, I'd cross the border near the middle and spend your first day riding up from the Stirling area and down Glencoe to Loch Ness, then across to the Isle of Skye via the bridge for the first day.
Base yourself on Skye for two nights, and spend your second day exploring the roads and scenery of Skye. Dont miss the ride across from Uig to Brogaig.
Then spend your third day in Scotland riding from Skye across the Armadale-Mallaig ferry, then across the Loch Linnhe ferry and back down past Loch Lomond and southwards.
Adjust for personal preference
Just my 2p worth
Rob