Unexplored places you can visit - Betul Lighthouse in evening,
Bhagwan Mahavir wildlife Sanctuary. Other best places in South Goa are - Palolem.Beach, Margao Market, Colva Beach, Benaulim Beach, Dhudhsagar waterfall.
The southern part of Goa is a peaceful place. Almost all beaches of south Goa are quite and less crowdy. But still some of the beaches you must visit are butterfly, arambol and cavelossim. If you want to visit a haunted place, try "3 kings church". Apart from this, I would suggest , you travel on your own and find out some unexplored place. The roads are very beautiful and you won't regret it.