If you want a full day tour - approx 8 hours from port in Greenock try the tour company discoverscotlandtours.com. Choice of 2 different tours and price is 87 pounds for either tour. Cancellation policy is 90% refund if you cancel 15 days before the tour. We are also on the Apex cruise on August 9th. We are thinking of signing up for the Loch Lomond, Stirling Castle and Trossachs tour