The Mount Ida Water Race Track sidles along the lower slopes of the iconic Hawkdun Range whose high, treeless, rockless, rolling, flat topped morphology is visible from much of Central Otago but doesn't seem to belong on this planet. It's isolated - there is not a cafe or cell phone tower for many miles. Nowadays the historic water race is an irrigation canal that carries water from the hinterland rivers to the dry plains down the valley.
The track along the canal is reasonably well formed and easy. It's not a smooth, hard and fast surface though and the local sheep love to camp on it so in places it's wall to wall dung. The ride up from Pierces Gorge car park follows a four wheel drive for about a kilometre and is a little steep.
Eighteen kilometres along the water race track you come to the Shephards Hut Creek Track. There you can go down to Home Hills Run Road and ride that back to the car park for a nice loop of about 31km (19 miles).
The Mount Ida Water Race Track and other walking and biking tracks are briefly described in DOC's "Oteake Conservation Park" brochure.