We went to NZ for a month back in 2016. I can't point out the highlights as the entire trip was amazing. Places visited, Kiakoura for whale watching, although we didn't see a single whale. massive earthquake 3 days after we left there. Christchurch is still rebuilding from 2011(?) earthquake Aoraki/Mount Cook National Park with a visit to the Tasmin Glacier, Milford sound, the drive from Te Anua is to Milford sound spectacular as was the boat trip out, make sure you have enough fuel as it's a 150 mile round trip and there were no services that we could see. Fox and Franz Josef glaciers are a must. We hiked on the Franz Josef Glacier which I thought was a great experience and was expensive as a helicopter is required to get you to the glacier and back, also the helicopter pilots require at least a 4 hour window of clear weather so as you can enjoy the hike and get back safely, We spoke to a lot of disappointed people who didn't get to go up due to the very changeable weather. North Island, we visited my in laws who live close to Mt Taranaki, Mrs wanted to go to Hobbiton, White Island to visit an active volcano and so much inbetween. We were told that on the South island it only rains twice a year, once for the first 6 months then again for the 2nd 6 months but we we extremely lucky seeing only two day rain in 30 days. I will once funds allow go back as it is a magical place.
Enterprise for car hire, all adequate, We flew between the island Auckland - Christchurch, food seemed expensive but we were only getting around $1.68 Nz - £1