Thanks for the further suggestions. We have pretty much decided on Montreal/Boston 5 days each now. I've gone off the train NYC-Montreal a bit having read some of the Tripadvisor reports because of its length, only economy cars, the bun fight at Penn Station and the delays at the border. So flying it might be. I'll have a look at the idea of Montreal-Boston by bus though i have bad memories off a previous Greyhound experience.