Is there a room where the guest can stay in there room and watch the monorail go by?

I don't think that there is .All rooms are above the rails .Rooms with park view and parking lot view would be able to watch from far

Yes. On the end facing the Magic Kingdom there is an area where you can see the monorail.

The monorail itself goes through the inside of the main building of the resort. You can watch it go by from anywhere in the Grand Canyon Concourse. If you have a theme park view you can watch the monorail make its turn and pull into the Magic Kingdom. Some rooms in the Garden Wing face the monorail line and can be seen from the balcony.