More than 20 years ago stayed at the Mont Joli. Was very comfortable then, photos look good today. Went with a group of friends. We flew in from Santiago airport (the old city airport) and the plane waited for us. One of the friends was the pilot. Was a great trip and my recollections of Cap Haitien was of a more green than expected town. Shopping for arts and crafts should be good.
Rode the horse up to the Citadel, but preferred to walk down. If doing it again would hike up and down. It is a taxing hike. You need to be in good shape. If you go, that should be the highlight of your trip. One can only imagine the sacrifice made by those who built it.