Travel recommendations for New England and NY State

Hi all,

My girlfriend and I will go to the US in August. We'll attend a wedding on the 15th in Philadelphia and fly back from NYC on the 27th. As I have never been to the city and my girlfriend loves it, we'll be there at least 5 nights, leaving us with around a week in between. We'd love to explore New England, but we will travel only by train or maybe by bus.

Generally, we are interested in seeing some nature, do some hiking and see the more rural/small town parts.

So far we have considered taking the Vermonter train, for example to Waterbury. Another option would be going northward along the coast. The third option I'm considering is going upstate NY somewhere.

Are these doable and worthwhile trips ? Any great recommendations for a carless one-week trip?

Obviously, if we could somehow avoid taking the same route from Philadelphia and then break to NYC, that would be awesome.

I feel a little overwhelmed with all the amazing places, but it's difficult to be sure the transport is doable and doesn't take up well of our time, so I'm sorry thankful for any advice!