Park or start at Fossheim Steinsenter (the mineral museum) and follow the path through the houses upwards to the field. Most of the log cabins you pass are hundreds of years old. Above the field is a pasture with a picnic spot and the cache can be found around here.
From there you can trek on a nature and cultural path to the top of soleggen (with a great view of the National Park Village) and you can also find the vassveg, an old irrigation system of wooden canals used to bring water to the dry valley from the mountains.