The Tumu Mountain Trail is a hard hike from the western end of Ofu up to the island's highest ridge at 491 metres. The trail starts near Ofu Harbor, initially follows an old road, and then climbs steeply through dense tropical forest with sections steep enough to need the fixed rope. The return distance is about 9 kilometres with nearly 500 metres of elevation gain — plan on three to four hours total and start early to avoid the worst of the heat and humidity.
The views from the ridge are what justify the effort. On a clear day you can see down over both Ofu and Olosega, the full extent of the reef, and the distant silhouette of Ta'u to the east. The lagoon below appears vivid blue-green against the dark reef line, and the scale of the remoteness becomes clear — you're looking out over open Pacific in every direction. The trail is closed on Sundays in observance of the local Sabbath; check with local contacts or the NPS before setting out to confirm it's open and in passable condition.