I'd check out the website www.hopstop.com .
It gives you ballpark estimates of how long it will take. Just put in your starting and ending addresses.
I work in NJ (secaucus) and live in Queens. It's a 1/2 hour train ride into the city and then a 1/2 hour ride (we have a company bus) into NJ... in the morning!
On the way home the ride from NJ into the city can be anywhere from 1/2 hour on a good day to 1 whole hour if there is traffic... I am expecting my first baby in April and this work scenario will no longer work for me... it's also exhausting... For instance office hours for me are 8:15 to 5pm which means that I am up at 6:00 leave the house by 6:45 and I am not back at home till 6:30 or 7pm on most days... I have been doing it for over two years now but once LO is here not sure I will be able to make it work.