We are getting to AMSTERDAM, ZEEBURG P&R COACH PARK AT ZUIDERZEEWEG on Wednesday morning (19/08/2015) and need to get to either Hanover or Wolfsburg.
Bus or train and which one is more cost effective?
You can get train tickets at DB bahn. If you buy in advance (say now) you can get saver fares ticket for a price of 39,00 EUR. This is for relatively faster connections: 4h 41min. If time is not an issue and you would not mind traveling 6h 35min and changing the train 4 time,there are options for 22,00 EUR. However later you buy more expencive your ticket will be here. The normal price of the ticket is approximately 75,00 EUR.
You can also take one of the following buses:
Those are also promo prices and might change.
There is also the option of car pooling. There is one person traveling from Amsterdam to Hanover on the day you want at 18:00. That will take a bit more than 5h of travel and cost you 24,00 EUR. Here is the add. And in general you can check mitfahrgelegenheit or blablacar websites to see if new posts appear for travelers from Amsterdam to Hanover.
As elsewhere in Western Europe, both are available, buses tend to be longer and somewhat cheaper. In both cases, there are discounts for advance purchase and the prices change depending on demand so you will have to check yourself to see how big the difference is for this particular trip.
There is in any case a direct train from Amsterdam Central Station to either Hanover or Wolfsburg (it's the same Amsterdam-Berlin train). It's not a high-speed train but perfectly decent. On such short-notice, the cheapest tickets are gone so you should expect to pay €50-70 per person. The full fare (always available) is a bit under €100.
When using the train, you can also save some money by sticking to regional trains (in combination with some special tickets) but that's more complicated (check earlier questions on this site for more).