Kerala is one of the most exciting place for a solo traveller. Places like Vagamon, Varkala, Alappuzha, Kochi, Munnar and Kozhikode in Kerala are quite interesting. Gokarna in Karnataka, Hampi which is also in karnataka, Ooty and Coonoor in Tamilnadu are few must visit places in South India.
Munnar, wayanad, allapey, ooty , kodaikanal,mysore, hampi, banaglore, chikmanglur, meshapulimala, kolukumala, cochin, thekadi, gavi. there is lots more. for write ups check my profile.
Karnataka and Tamil nadu is the best place to travel as you will find good roads and great food along the way and you can appreciate the beauty of western ghats