Depending on how many passengers are going on the tour, I would also check with DenRus. If it is a small group (1-3 or 4) DenRus might be a better choice as they will accommodate tourists in cmall cars.
They will have a ball.
BTW, here is a link to the thread SunPrincess mentioned. I think it will be quite enlightening.
http://cruise-chat.com/eve/forums/a/...1/m/9041063421
Tom