There is a way to take the whole family on a road trip and not spend hundreds on campervan rental and that is campervan relocation in NZ. This is where a vehicle has been leased and driven to the destination and then left at the local rental outlet, the van then needs to be transported back to the original location. So instead of loading all of these stranded vehicles onto a transport truck the rental agency would much prefer to give you a discount on rental fees and have you drive it back for them, they may even chuck in the fuel and insurance costs for free. Saves them both time and money doing it this way and they can have their vehicle back sooner and ready to be leased out once more. Otherwise they have to wait until they have a full load of vehicles to put on the trucks for transportation and this can take some time and not all the vehicles will be going to the same place.
Some rentals will be just a dollar a day to hire and that is a huge saving on your trip, if you are really lucky you will be able to find a vehicle to take you to your destination and another for the return trip saving you bucket loads of cash in the process. There is however a catch in that you generally need to have the vehicle back at the original rental outlet before a certain date, so this is not the sightseeing tour that you were planning on taking, instead it is just so you can get from point A to point B in the shortest time possible and without all the expensive costs involved. This means long hours of non-stop driving so that you can reach your destination in time and you will need two drivers to do this responsibly and safely. If you do the planning carefully and keep within your time limits you may be able to get a little sight-seeing in but don’t be too sure of it and keep in mind all the conditions that you may encounter on the road.
You need to take into account bad weather, road works and possible crashes holding up traffic and then there is the traffic itself if you have to go through any major cities on the way, try to hit the big populations during non-peak hours so that you can get through as quickly as possible. Around two in the morning is a good time as the roads are nearly deserted compared to day time driving. In fact keeping the driving to mostly night time will smooth the driving considerably, hazards are harder to see and there is more risk of collisions with wild life but the advantages of car relocation Wellington to Auckland are of having highways to yourself and not having to battle through the crowds.