Any place in the State of Himachal Pradesh would be great for a solo travel. It is safe and people are very much courteous. Also, Hampi in Karnataka would be great if you are more of a history and architecture lover and also low on budget.
Any place would be fine if you have the fire to explore.
Start with Hampi, Gokarna, Dharamshala, Mcleodganj, Spiti, Parvati valley to get a divine taste of it.!
Meghalaya... because it is such a beautiful state with so much cultural diversity to offer. the people are very kind and friendly... you'll never have an issue with stay or language because the people are generally so warm and welcoming. Hindi and English are mostly understood all over and it is a very safe place for solo travellers.