We did a 3 day trek from Kaza to the villages around it . The trek was nice and really allowed us to get to know the villages and people of the Spiti valley. The walk wasn't hard, between 4-6 hours of walk every day with just one relatively small crossing on the second day. To organize it we got some guidance from the nice people in Ecoshpere who are helping the people of the valley's villages to organize the homestays in which you sleep thourghout the trek.
Watch out fot the weather and make sure you are accustomed to the heights as the trek starts at 4200m and just goes higher.
Otherwise you are in for a treat of local life and mountain views.
"…From the top of Mt. Oberon you can see a breathtaking view of the south-west side of the Wilsons Promontory National park. The rocky beaches are composed of small inlets, the sea is blue and calm, and there are many islands near the shores.
The water is very clean and clear, with a special hue of turquoise. Giant boulders spill into the ocean between the inlets. As the evening settled in, we went to watch the sunset from Norman Bay. A spectacular view not soon to be forgotten".