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/13 yrs exp and 48 Cruises on 11 cruise lines! Favorites: Paul Gauguin - Tahiti: Uniworld River Cruises - Europe; Celebrity Solstice-class ships; Holland America - 12-nights Baltics & Russia; RCCL - 14-nights Greek Isles, Turkey, & Croatia; Holland America - 14-day Alaskan cruisetour; 10-night Canada/New England cruise; 21 days Hawaii w/7-night NCL cruise; Oceania - 25 days in Asia; more than 3 months touring Europe by train. And many all-inclusive resorts!