Toured the South Island of New Zealand with 3 friends in a Mitsubishi mini-RV. We always had the fridge stocked with cans of Victoria Bitter (VB), which is some of the best beer in a can going!
The scenery as you drive around is awesome, and all the windows in the back of the motorhome made it practically panoramic. Driving on the right-side of the car and on the left-side of the road was a bit of an adjustment, but aside from the middle of the biggest cities, it was a total piece of cake.
We had no trouble finding suitable places to car-camp. We enjoyed a variety of activities. In Kaikoura, we took a coastal hike through a sea lion colony and a gull colony, did a whale watching tour, and swam with sea lions (the dolphins one was sold out). Highly recommend the visit to this seaside town.
We golfed in Hamner Springs and Wanaka (basic public courses, though Wanaka's had scenic views of the lakes), river rafted on the Buller River, did a glacier hike on Mt. Cook (with small plane landing), and did a 2-day rainforest backcountry hike (overnight in a hut).
Queenstown has every adrenaline activity you can imagine and then some -- we did bungee jumping and mountain biking while we were there. Later, had some fun watching the penguins come ashore and return to their nests in Oamaru and did some Christmas shopping on the last day in Christchurch (the wool products are especially good).