My family and I visited Citadel Park and of the museums this was our favourite. We particularly enjoyed seeing the Belgian art and Cameron's photography pieces, finding the guide to this particularly insightful. We would visit again given the opportunity.
On Wednesday you can ask a renovator of the Mystic Lamb about his work. The museum is not so big: it is renovated not that long ago. A would recommend a visit during the week when the painters are in the house in combination with a visit to a special exhibition.
This museum is fairly run of the mill except for the ability to watch the work being done on the Altarpiece from St Bavo. It is amazing to watch the restoration.