Matheran is a good option away from the hustle and bustle of the City. Vehicles are not allowed inside this beautiful hill station. Horses are the only mode of transport inside Matheran, which makes this small hill station so special. You can catch local train from Thane station to Neral and start your trek from Neral station which is only 7km away from Matheran
You should go For Harishchandragad Trek. That's really a good option for you to explore Raw nature at it's best. YOu can camp out near the Cliff of Konkankada. if you wish to know more details about it, drop in a message and I can help you with the same. Thanks.