I live in Panvel since 1994- from a time when there was no train to Panvel.
Now that it boasts of a large terminus, it's useful to know that the last train to Panvel from VT (CST if you prefer) is at 00.43 am. For someone who has been a commuter on Bombay's suburban trains forever, it's a ticket to wander around the city till midnight and a little beyond. If you have also taken this train as I have done many times, you would know how many people are on board. Workers, men and women working in late shifts in myriad establishments across the city are your co-passengers. Crowds are that are a nightmare at usual hours now appear comforting and reassuring.
Of course, if you for any reason miss this last train, there is always the first train at 4.24 am which you can board after having a break fast of baida pav and chai outside the station (only chai for me, though).
It's never too late or for that matter too early in this city.