Trailfinders may well be worth a chat, they do have "shops" as well you could go in and speak to someone face to face. I found them fantastic booking for Canada (nothing quite so adventurous though!) as did other family who did more travel (rail from Toronto to Quebec and back via Montreal and Ottowa) - I think Trailfinders sorted everything out for them.
It's a big place so make sure you consider that when booking travel as journeys can be very long!
If you go to Niagara, definitely do the Maid of the Mist (the boat which goes out right the falls) - incredible! Wasn't so impressed on the Behind the Falls (tiny little holes!) but they have a platform out bearer the bottom of one of the falls which is great! Prepare to get wet :)