From Toya Bungkah, walk one hour or drive the single-lane, surfaced road to Songan on the northeast corner of the outer crater, 12 km from Penelokan. Songan is also accessible by boat from Kedisan and Toya Bungkah. This is the largest village on the lake, with a population of around 5,000. The people make their living from fishing and cultivating the flatland beyond the village. The remote hamlet has only one losmen, Restiti Homestay & Restaurant, with simple rooms with bath for Rp12,000; it's located on the road to the temple 200 meters beyond the village. There are no bemo to Songan but you can get rides on gravel trucks; the drivers ask for lots of rupiah but are happy with Rp2000; some travelers wrangle free rides. Many sulfur wells and natural springs in the area. If you need to go back up to Penelokan in your own vehicle, gas up here.
Turn right at Songan and travel to the end of the road to reach beautifully situated Pura Ulun Danu (not to be confused with Pura Ulun Danu in Batur village on the western rim of the crater). Since the headwaters of Lake Batur are considered holy throughout the whole eastern half of Bali, a ritual drowning of live animals occurs here every 10 years in honor of Dewi Danu, the goddess of the lake. In 1994 two buffalo, a pig, a goat, a goose, and a chicken, adorned with gold, kepeng, and other decoration, were taken out into the middle of the lake and drowned with solemn grandeur. The floor of the lake is no doubt littered with incalculable wealth from the millennia of ceremonies since it's believed Pura Danu Danu was built on the site of a pre-Majapahit temple.
From the temple, climb 15 minutes up to the remote viewpoint on the crater rim; you can see Bali's east coast. It's a 12 km walk on an old trade road to Lupak on the Amlapura-Tianyar-Tejakula-Singaraja highway running northeast along the east coast. Walking downhill over streams and through little villages and beautiful forest areas, it's about a five- or six-hour hike. Take water, as the more you descend, the hotter and more barren it becomes. The path ends in the middle of Lupak's small local market. Turn left on the highway and catch a blue bemo to Lovina for around Rp3500.
Right behind Pura Ulun Danu, a small footpath climbs up to the rim of the outer crater. The right path then winds up to Gunung Agang, passing above Trunyan—an arduous climb. The path to the left leads down to the traditional village of Blandingan from where a path will take you back to Songan.