For all of groups larger than 12 paying participants, you will have your own luxury bus throughout your tour. The only exception to this is that in capital cities, for groups of under 25 participants, we often find that the local metro system is a more efficient way of moving about the city. As always, the choice is yours. For groups of 12 or fewer paying participants, we normally have a smaller bus with a driver/guide.
If your itinerary has a day with a large distance to travel, we may use a train if it improves the quality of the tour. For example, if you were taking a Provence, Paris and Normandy tour, we would use the TGV (fast train) to transfer between Paris and Provence. This would take three and a half hours instead of twelve, giving you an extra half day as well as saving you a tedious bus journey.