The road which goes to Bankey Bihari Mandir once you cross ISKON temple has paid parking on both sides. Or there are grounds in front of Prem Mandir with adequate space. They charge high but safe. However prem Mandir is far off from Bankey Bihari Mandir. This is the only option other than to park at various Ashrams or hotels which have got their dedicated parkings. Decide as per convenience.