Motueka is a great place. Looks on the map like a small place to pass through on the way to Abel Tasman, but there's a lot to do there and for staying for a while there can't be many better towns in New Zealand. Small but with the facilities and nightlife of a much larger town, extremely friendly and welcoming locals, arguably the best climate in New Zealand, tons to do within easy driving distance. I'd stop here for at least a week and make it your base for exploring Abel Tasman and Kahurangi National Parks. Though this is really the sort of place you'd want to live permanently someday, you don't get the full appeal of it in a few days. Other than the obvious attraction of Abel Tasman, Golden Bay is well worth a trip over the pass to visit Farewell Spit and the Pupu springs (very good on a day with nice weather, far better than you might imagine) among other attractions. What I would most recommend though is the trip up Mount Arthur to the flora carpark (steep, unsurfaced road but easily achievable in a two-wheel-drive car or campervan) and then up the trail to the Mount Arthur Hut and beyond. Nice walk through the native forest up to the hut, takes one to two hours depending on how slowly you take it, but don't be tempted to turn back there as I was the first time I went up. The hut is at the treeline, carry on for another ten minutes to come out on the tops and be rewarded with some of the best views you will ever see in your life, I say that without hype. Seriously incredible, going up there was like drugs, I went back half a dozen times and would have carried on doing so if I hadn't left to fly back to the U.K. Easy walk on a good surface too, even in the winter. The wild Kea parrots up there that will fly down and walk around a few feet from you if you are lucky are the icing on the cake. You can carry on further up all the way to the summit of Mount Arthur if you have the time. Don't miss this out - it was the highlight of my whole six months in New Zealand, and it's one of the first things I plan on doing when I go back.