There is mass trekking event happens once in every year in Nallamala forest near Srisailam Dam. Forest department opens one day for trekkers to visit a shrine surrounded by deep forest and few water falls. Attended by thousand people every time. I heard this is a moderate trek, not very difficult. About Saleswaram ; Saleswaram, Situated 60 Kms north to Srisailam inside Nallamala Reserve Forest, Saleshwaram, also known as Sarveswaram and Saileswaram is famous for a Shiva temple built in 6th / 7th century AD. This temple is open for only once an year during Chaitra Poornima. Check this link for details of Saleswaram. https://hamsalekhha.blogspot.com/2016/06/saleshwaram-trek-deep-into-nallamalla.html?m=1