I second that: Engadin is the place for you!
i.e. Samedan could be a good (and less expensive) base for you to explore GraubŁnden.
Here is one link http://www.samedan-ferien.ch/
I hope you find what you are looking for!
Enjoy your vacations!
PS. I'm a big fan of Kobenhavn-just love this city!!