Wellington Region includes our capitol city, and extends up the Kapiti Coast and the Wairarapa.
While there is not a lot for motor caravanners in Wellington city, it is the gateway to the South Island, with two ferry services. Overnight parking is available at the Te Papa museum, as well as campsite parking within the harbour area,
Further north, you have a range of beach front communities to explore up the Kapiti Coast. The beaches are typical west coast pebble beaches, but there are some interesting locations.
The south Wairarapa is a completely different environment - with a large fresh-water lake, rural communities, and some scenic (mountainous) drives.
There is also New Zealand's own Stonehenge to explore - an fully working henge as was widely used throughout Europe for tracking the seasons.