The Okataina Western Walkway track runs between SH30 at Ngapuka Bay on Lake Rotoiti to Millar Rd near Lake Okareka. In total about a 7-hour walk according to the DoC site. The northern end from SH30 to Lake Okataina is a walking track only. The remainder of the track is both a walking and mountain biking track. Supposedly the longest mountain biking track in the Rotorua area at 19.1km.
This post covers the northern end of the walkway, from SH30 to the Patotara exit point, a distance of about 4 km.