I visited Dumka last December with my friends and had a mixed experience in the city.
Firstly, the weather was really hot even in winter like around 27° Celsius and most of the areas became dry.
There were not many places of local sightseeing but places like Baba Basukinath Dham, Baba Sumdshwar Nath Temple and Massanjore Dam were quite popular as tourist places.
The roads were in poor condition and the being quite small not well connected.
Transportation were not easily available especially at nights and charge heavy fair even for smaller routes.
The quality accommodation were not available in the city as the hotel tatiffs were very cheap.
The city is relatively safe at nights as the city has low crime rates with people being largely good against each other.