Roads through this region's mountain ranges and deep river gorges can be narrow and winding, and a 160-km (100-mile) drive might take more than three hours. However, the roads are generally good, and there's always something to look at. There are a number of one-way bridges along the way. Check the road sign with two colorful arrows: if the arrow is red for your side of the road, that means you give way if traffic is coming the other way. Remember always to keep left. It can also be a long way between gas stations, so fill up when you can.
Nelson is about a two-hour drive from Picton. From Nelson, State Highway 6 runs southwest to the West Coast, north to Westport, back south down the coast to the glaciers, then inland, over the Haast Pass where roads lead to Wanaka, Queenstown, and Central Otago. For the West Coast, count on at least seven hours solid driving (and photo stops) for the 458-km (284-mile) journey from Nelson to Franz Josef. (But seriously, don’t even think about doing this in one haul. Take a few days.) For Nelson to Christchurch, allow up to five hours, whether you go through the mountains of the Lewis Pass or take the coastal route via Blenheim and Kaikoura. Heading direct west from Nelson, Highway 60 splits from State Highway 6 about 13 km (8 miles) out of the city, near Richmond, and continues to Motueka, Abel Tasman National Park, and Golden Bay.
Westport, gateway to the northern end of the West Coast, is roughly a three-hour trip from Nelson on State Highway 6 or a five- to six-hour drive over Arthur's Pass on Highway 7 from Christchurch. State Highway 7 climbs from Arthur’s Pass and across the backbone of the Southern Alps before winding steeply down through rain forest to the tiny town of Otira and on to the coastal river plains of the mid–West Coast.
Some car rental agencies have North Island–South Island transfer programs for their vehicles: you leave one car in Wellington, travel as a foot passenger, and pick another car up in Picton on the same contract. Others let you keep one car that you drive on and off the ferry. Check first.