Was in Kolkata for a short business stay and had booked Emerald after reading all the good reviews here. Wasn't dissapointed.
It is easy to miss the first time you arrive since the name board is tiny. The houses are numbered here, so if you give the house number (B6) to the cab driver, he should drop you right outside the gate. A team of four boys manage the guest house, right from assigning rooms to cooking to cleaning the rooms. There are only a few rooms and only so many occupants, so personal attention is given to every customer. Food is excellent, almost home cooked. Though it takes a while to prepare since they prepare it fresh. Breakfast is complimentary.
Salt lake is pretty accessible, it is only 30 mins from the airport. Uber taxis are readily available.
Allin all, we had a great stay!