The Moxy hotel is a 5min walk from Terminal 1 at CGN and it offers limited views of movements at CGN.
The hotel has 5 floors - with the reception area, bar and restaurant on the top, 5th floor. The restaurant/bar has an outdoor area that will allow views of all movements on approach or departure (you can't see the actual runways or taxyways as they are blocked by the terminal, car parks, etc). From indoors and outdoors on the 5th floor you can get some views of part of the remote stands off terminal 1 (also used for freighters) and the military area.
The hotel has 5 sides as well as an internal void - any of the internal rooms will have no views at all. Rooms on the outside have differing views...
Preferred rooms would be those ending *34/35/37/39/41/43 as they look towards the airport and therefore give views of aircraft arriving on 32R or departing off 18L. While not verified as movements are rare on the two other runways, I would expect you'd be able to get similar views of landers on 32L or departures off 18R and the Cross Runway movements should also be visible. However most movements are on 32R/18L, so these should be the best rooms available. The higher the floor the better.
On my last visit I had room 253 which, while not an ideal angle did give views of the 32R approach. Compare the map below to google maps for an idea of other angles.
https://maps.app.goo.gl/NfvuJKSzDEs6y39B7
