trains round east coat: boston to NYC and also to travel to montreal/toronto + general info please?

Ok so we're planning on going to the east coast round 15th September for 10days. nothings planned yet but maybe boston first for 2/3 days canada and back to NY. whatever way have to start in boston new york or chicago because we have to fly with aer lingus home to dublin.

any itinerary advice?? trains, areas to stay etc
thanks
re budget: mid price generally 3stars hotels

Your best bet given the time constraints will probably be Amtrak.

Something along these lines maybe.

Day 1 - Arrive Boston
Day 2,3 - Explore Boston
Day 4 - Transit to Niagara Falls, ON (stay on Canadian side)
Day 5,6 - Explore Niagara (my hint, when doing the main attractions, by the two day pass and start at the Farthest first (the butterfly garden). You will miss most of the tour crowds as they all start at the other end.
Day 7 - Transit to NYC
Day 8,9 Explore NYC
Day 10 - Homeward Bound

Specific stay recommendations I can't really do without an idea for budget.