I'm visiting relatives in Montreal but would like to see a bit of North America too if possible...I'm only going for 2 weeks maybe a little bit longer.
Any suggestions where to fly into/ from and border crossings? I'll be coming from Munich, Germany. And which direction is easier...USA to CA or vice versa. Which places could be possible to visit in that part of the country? I've read that trains might be an alternative to flying? It would be a whistle stop tour I know but I'm keen to see as much as possible, last time I was just with the family and didn't get to see anything.
I'm interested in seeing natural/ historical / significant sights and trying local cuisine rather than shopping. I'm going with my boyfriend, no kids, late 20s/ early 30's, both fit and healthy.
NY and Niagra falls are the obvious choices..but where else?
Any advice greatly appreciated.

thanx in advance
Immigration

why not take a trip to nyc and not niagara falls. In nyc you can see lots like the statue of liberty, empire state building, museums, times square, the MTV studio, central park, Bronx zoo, Brooklyn botanical gardens , Coney island etc. Yea you can't do all these in a day but its an idea