1) I have no idea what the taketours trip is, but if it's leaving from Chinatown, it's likely on a Chinatown bus which are notorious for being unsafe with unsafe drivers.
2) The GWB I'm assuming is the George Washington Bridge. There is no subway station there but there is a bus station. The nearest subway station, according to Google maps is a 5 min. walk and I'm not sure that's a safe area to be walking. I don't know who's dropping you there, but it's a lousy place to be let off.
Here's a link to travel options from google maps. All the numbers are different subway lines. Perhaps someone else with more on the ground knowledge of that area can weigh in on safety and practicality of this plan.
The 175th Street A train station is directly connected to that bus station; you don't have to go outside into the neighborhood. Take the A train downtown to 59th Street and there switch for the D train, following on the same platform, to Grand Street.
However, as nywhiz says, that tour sounds really shady. Many of the companies down there are known for poor quality drivers, unsafe buses, and "tours" where the "tour guide" hardly speaks any English.
Anything leaving from 48 Bowery is a huge red flag to me.
Why are you going to be at the George Washington Bridge? Is that what you mean by GWB?
The 175th Street station on the A train is connected to the George Washington Bridge Bus Terminal. That is fine - even if you have to do it at 6:30AM - perfectly fine.
You're from Pune.
The tour companies who operate out of 48 Bowery are the US equivalent of the guys with rickshaws who sit outside of any Indian train station waiting for wide-eyed NRIs or white people to get off the train and saying, "you want tour? you want tour? all the sights," and then "my cousin has beautiful carpet shop, very low price."
Just like in India, go with reputable, large, national, city-center tour companies, not these dudes.
LOL!!! Well I read the reviews of taketours.com, and they seemed pretty ok, so thought I'd take one of those to Niagara.
and yes I did mean the 175th street station.
You know it is very easy to create fake reviews? Yes?