I have recently visited Matheran this year.every year atleast one time I going matheran specially in between Monsoon.
The Matheran fully wraped with Nature beautiful things. It is very nearby Mumbai and you can go there by using train then taxi to reach Moutain top.
You can not enter inside matheran with personal car as this is very nature senistive area. I have enjoyed Horse ridding here. Lodge is also chip and good. Food is not that much great. There are many point where you can go for photo shoot. The senere is very good big mountain, Waterfall and surrounding is very green and green. I will defenatly recommend this place for picnic.