Taking the train from Boston to New York City in August. We are staying that Grand Hyatt which is very near Grand Central Station... is there any way to arrive in NYC from Boston at Grand Central?
Also, are there trains from Cape Cod to NYC? We planned to drive from Cape Cod to Boston to board the train -- but if there is train service (and a place to drop a rental car) on the Cape - it would save time. All suggestions are appreciated!

Amtrak uses only Penn Station in NYC - not Grand Central. And I';m not aware of any trains from Cape Cod to NYC.

If you really wanted you could get off an Amtrak train at one of the major train stations in CT - for instance New Haven - and then take a MetroNorth train into Grand Centtral. Have no idea what this would do to your schedule of fares though.

Why not just grab a cab from Penn Station to the hotel? It won;t cost more than $10 or so - and would seem easier than switching trains/finding the right tracks etc. while dragging your luggage.

There is no train from Cape Cod to New York City, but there's a bus - Peter Pan/Bonanza operates a bus from NY Port Authority to Hyannis, which takes about 5 hours.

Check a map and you'll see that there will be much less backtracking if you board the train in Providence rather than Boston.

It would make more sense to drive from Cape Cod to Providence for a train to NYC rather than going back to Boston. It'll be cheaper and will take less time to get to your destination.
As previously mentioned, no trains from Boston go to Grand Central. I would prefer to take a cab from Penn Station to the hotel rather than changing trains in New Haven or Stamford.

Thank you for the advice! I will definitely check into the Providence station instead of Boston. Thanks Fodorites! As an alternative, how is the drive from Cape Cod into NYC? (drop off the car in the City).

You can always take the subway to Times Square then the shuttle to Grand Central however depending upon time of day (rush hour) and how much luggage you have this may not be the best idea.

The drive from Cape Cod to NYC is long, but depending on how many are traveling, might make sense. Your other option is to drive from the Cape to Logan airport and fly to NYC. Because so many people use the train to go from city center to city center, the airfares can sometimes be cheaper than the train. You have to add transport to/from airports in NYC but not to Boston airport if you're driving.

The drive is not bad at all. Probably about 4 1/2 hours or so from Hyannis area.