Bangalore to Lepakshi is about 125km by road. Take the NH7 out of Bangalore. About 10km after Bagepalli junction, leave HN7 to the Hindupur. Lepakshi village appears before you reach Hindupur. There is also a route back to Bangalore via Hindupur.
Bangalore –>16km –>Yelahanka –>22km –>Devanahalli –> 21km–> Chikaballapur –>41km–> Bagepalli –>25km–> Lepakshi
What you see today as the 'Bangalore Fort' is actually a tiny remain - rather a gateway portion - of an otherwise sprawling fort that stood as the prime landmark in the old days of Bengaluru.