Mathura, the land of Krishna, the place where his uncle was slain by him, later is certainly a place to reckon with if one wants to completely enjoy Krishna Janmasthami.
You could never come back disappointed if you visit the places in Panchgani- the land of the five hills. Just go there, enjoy and come back to endorse my view.
Trimbakeshwar is one of the holiest place not only in Maharshtra but also all over India, in close proximity to Nashik, it also comes under the twelve Jyotrilingas.
Nagarjuna Sagar Dam is the world's largest masonry dam built across Krishna River in Nagarjuna Sagar, Nalgonda District of Andhra Pradesh, India, between 1955 and 1967.