I've been to elephanta a couple of times ...its a good place for a day trip with friends or family and the boat ride is quite pleasant. Its best during winters when the sun is not too hot and the sea not too rough.
There are many ticket agents close to Gateway of India selling tickets for the boat ride. There's not much of a difference in prices but its better to ask a few before buying. The boats usually leave at half hourly intervals from the dock.
There are not many options of eating so carry your own food and drink (please do not litter)...the caves are on a small hill and the steps are bordered by endless vendors selling junk jewellery....please do bargain as the prices are tourist inflated. ..you'll also find a lot of vendors selling fruits, roasted corn and peanuts
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.