Matheran is generally regarded as a safe destination for solo female travelers. Like any destination, you need to take general precautions with your belongings and be mindful of your surroundings, especially during evening hours. The locals are generally very friendly and it's a frequented tourist spot, so you won't feel out of place. Do remember, proper dress code is important in India. Avoid secluded areas and as long as you follow these, Matheran can be a safe and enjoyable destination.