I would be wary of making reservations. Your trip is long, and will prove to be full of surprises. Some will be unwelcome, for example a sudden need for a new tire. Others will be more pleasant, such as an unexpected invitation to stay a few days at a cottage. If you feel that you need to get to a reserved room that is distant, in unpleasant weather, you may wind up riding when you are uncomfortable or fatigued. Such rides are not the stuff of holidays, and can be hazardous.
I rode from Toronto to Vancouver to Toronto, about 10,000 kilometers, in 2006. I often slept in my tent, but when I wanted a motel I looked for one and found it, for example in Coeur D'Alene Idaho or Battleford Saskatchewan, and I never had a problem.
I have made lots of trips (see maps below) and usually knew very little about my route before setting out. I have missed a lot of sights, but I have seen enough of them to make the long rides worthwhile.
I think it's good to have a major objective, and here is one you may consider for a future trip: Louisbourg Nova Scotia. The entire fortress town has been reconstructed, and it goes about its business much the way it did almost three hundred years ago. It is surely worth at least an entire day, but if you try it and don't like it, there is an entire province around you, offering many ways to have fun or learn things.
Whatever plans you make, you will be very lucky to achieve half of them, so do be flexible.