To clarify,-Tauranga is actually another hour(ish) further on from Auckland than matamata --where hobbiton is. Tauranga is a lovely area and I'd suggest going there definitely. Then back up Via Waihi gorge.
This is an interesting one.
The trouble is, if you only have that period of time, it would be very frustrating, tantalising, and irritating, to catch a glimpse of all Rotorua has to offer and then have to return to Auckland in the late evening.
Tauranga and Mount Maunganui are both pretty, set on peninsulas poking out amongst bays and estuaries into Tauranga Harbour; but they are working cities, and while tourists are welcomed, neither city actually NEEDS them, unlike Rotorua. The Mount has its beaches, and has the longest wharf of the Port of Tauranga, the country's largest port by volume, exporting pine logs, kiwifruit, and dairy products around the world. Both are very pleasant places to live, with a mild climate, many parks, a few historic buildings, and the spooky Monmouth Redoubt, used during the New Zealand Wars, fought because the settlers wanted more land, than the Maori people wished to sell. Some ideas are heading up Mount Maunganui (Maunga - mountain, nui - big, proper name Mauao - difficult to translate, along the lines of "caught in light of day."); exploring Tauranga which aptly means "sheltered anchorage", and its art gallery, aircraft museum at Tauranga Airport, and there is The Elms, a historic mission house, which can be visited too.
If this is too many options, Rotorua gives far, far, more, and is truly worth a visit on its own.
Another option, after Hobbiton, if you are feeling energetic, is to head up to Wairere Falls in the Kaimai Ranges, which is a very steep but rewarding tramp, about two hours in all. It is 15km east of Matamata, off the Old Te Aroha Road. Then return to Auckland.Edited: 20 January 2015, 10:59
Thank you so much for the encouragement and historical perspective. We have Rotorua scheduled for a later date. We are flying into Auckland after a cruise, meeting our granddaughter who is on winter break from an assignment in China, spending a couple of nights in Auckland in order to visit Hobbiton, and then flying to Christchurch to tour South Island. When she departs we will take the train/ferry from Christchurch to Wellington then drive up the western coast, across to Rotorua and to Auckland through the middle of the country. There are so many beautiful places we'll miss, but have limited time. Our driver guide who will meet us in Auckland prefers that route.
Thanks again. I've spent months pouring over maps, reading reviews and trying to maximize our experience without hurrying too much. Wish me luck. We leave home January 26 and arrive in Auckland February 10. Can't wait!
Definitely drive back to Auckland via Tauranga/ Mt Maunganui if you have the time, it's not called the scenic highway for nothing. BUT it would have to be a fine day otherwise there's no point AND you must drive the little bit extra when you get to Tauranga over to the base of the Mount (Mt Maunganui) and check out both the ocean beach and the inner harbour around Pilot Bay. Better still walk the Base Track (40 minute easy walk) or to the top for fantastic 360 degree views if you're feeling energetic. It's actually only about a 40 minute drive from Matamata to Tauranga too but up and over a small range with fast cars so take care.
Here's my blog post on the Mount (was my home town for the last 25 years)
Here's the link to Mt Maunganui walking tracks, look for Part 2 out in the archives on the right (for December)-
The road over the Kaimais (the mountains between Matamata and Tauranga) are best not driven in wet weather - otherwise do take them carefully - but the Mount is worth it. The Mount area is/was in recent history, a popular summer holiday destination - the permanent population there is growing.
On your way back to Auckland you'll take the route through Katikati, Karangahake Gorge, Paeroa, Waihi, Ngatea... K-Gorge is lovely for a walk, Paeroa has great antique stores...
If you want - you can head from Matamata straight to Paeroa, rather than going to Tauranga.. see how tired you are feeling and how the weather is etc...