I suggest looking at Shore Trips. We've had great success with them.
We've got another vendor, but unfortunately we're on travel right now and I don't have access to those files. When I get back, I'll try and let you know who they were as several clients have used them and were very happy.
But this is one place where you can get a much better tour than going through the cruise line.
__________________ Travel Agent/Cruise Specialist w/15 yrs exp and 50 Cruises on 12 different cruise lines in many parts of the world! VIETNAM VETERAN OWNED & OPERATED. Certified Accessible Travel Advocate. Specializing in unsurpassed personal service to insure you have a hassle-free vacation!