From Richmond, south of Nelson, there are two routes to Motueka: the quicker, busier route along the Ruby Coast, and the inland route through the Moutere Hills. If you're making a round trip from Nelson, drive one route out, and the other on the way back.
The two highways aren't particularly far apart, and the whole area can be explored by bicycle on the Great Taste Trail, so named for the many wineries and other culinary (and art) stops along the way. The Nelson Wine Guide pamphlet (www.winenelson.co.nz) will help you find them. Other useful resources for this area are the Nelson Art Guide and Nelson's Creative Pathways pamphlets.