The trail rises from 2,150 m at the gate to 2,776 m on the rim in about 3.1 km. The climb is steep, dusty and entirely exposed; allow 45 minutes to an hour. From the rim you can either turn around or walk the full 7.2 km circuit, which dips and climbs over several minor peaks and finishes at the true summit on the western side at 2,886 m.
The views are extraordinary in both directions: down into the forested crater on one side and out across Lake Naivasha, Hell's Gate, the Aberdares and (on a clear morning) Mount Kenya on the other. Bring at least two litres of water per person and start early — the afternoon haze rolls in by midday.