Take a stroll all the way up Tobin's trail, past Tobin's cache, and on up the track to the lookout. At a good clip it's under 30 minutes, or a 40-50 minute leisurely stroll to the top.
The small black cache is about 70 metres past the top, on the way down the alternative (steep) trail that takes you back to the Millennium Trail that takes you alongside the Arrow river.