The main attraction of Devarayanadurga is the Yoganarasimha Temple. There is road till the hill top and the view of the plains from here is awesome. There is a series of hills known as Devarayan Durga Hills ( DD hills ) near by which are easily trekkable like Ramadevarabetta.
Anytime other than monsoon is okay. September to may is a good time to visit.
It is better to carry food while visiting the place. Shops selling snacks and drinks are available at the hill top.
Route 1: Bangalore - Nelamangala - Dabaspet - Devarayanadurga.
From platform no:16 in Kempagowda bus station you can easily get a bus to Dabbaspet. After reaching Dabbaspet autos are available to the hill top.