Hi Pravesh, that is such a noble task that you will be doing. I recommend the following pilgrimage sites: Dwarka and Somnath in Gujarat, Rameshwaram and Madurai in Tamil Nadu, Puri, Bhubaneswar and Konark in Odisha. I want to say Haridwar and Rishikesh as well but it might be slightly chilly there as temperature could go as low as 6 Celsius. Varanasi is also a good option.