If you are travelling from Mumbai you have the option of travelling in a boat. There is frequent ferry service from the Gate way of India who would drop you to the Alibaug bus depot. Nagaon is jus 8 Kms from the depot.
Alibaug town is about 100 kilometres from Mumbai. Once you reach the Alibaug circle take the Alibaug - Revdanda road. 7 kms ahead you will reach a "Shivaji Statue" which is the landmark for Nagaon. A right from the Shivaji Statue towards the Nagaon beach takes you to Kalpavruksha Lodging.