To tell the truth, the buses are being used mostly for reginal transpor. As far as the longer distance travelling is concerned, the train would be better (with the exception of north and north-east part of Holland, where train traffic is less frequented or no train connection exists there).
The trains in Netherlands are quick and could save you a lot of time, provided your travelling programme could be busy. InterCity trains between all big cities pass each 15 minutes. There are several sorts of reduced types of tickets, such as: return tickets, day-tickets, etc.
If you decide to travel by car, you have to conclude security police (Green card). The traffic is led on right side, whereas maximal permitted speed in the community is 50 kms/h (outside towns 80 kms/h and on highways 120 kms/h.
You have nearly 10000 kms of cycling routes available, and so, you have the chance to enjoy fully cycling travelling in the Metherlands. To tell the truth, expecpt highways, you can drive on your bicycle, practically everywhere. More than 85% of local population are travelling by cycle, and bicycles are even morethan inhabitants.
Information and warnings on travelling abroad is to be found HERE.