Head south on SH5 from Rotorua city. 1 km from the city limit on the left you'll find the Waipa Mill, the entrance to the Whakarewarewa Forest.
Shuttles are available to the entrance of many trail starts.
To ride to the entrance from the Waipa Mill carpark, ride up the Waipa State Mill Rd which will turn into Hill Rd. Follow this for 5.5 km until Moerangi Rd appears on your right, 1 km on this and turn left onto Tawa Rd after 2.5 km you'll be at the highest point in the forest and at the start of the track.