My spouse and I were visiting Saint John's for 3 days and wanted to take in all the most famous tourist attractions. We were told it takes most visitors 2 hours to make their way through all the Rooms. We skimmed quite a lot of the exhibits and it still took us 6 hours.
We ended up going to the cafe for lunch as it was taking much longer than we expected to make our way through. The cafe is a licensed full-service restaurant with gluten-friendly and vegan options.
Our main criticism of this largely awesome museum/art gallery was that the World War 1 exhibit didn't have a content warning at the beginning of the exhibit. There are graphic images within the exhibit that I wish I hadn't seen, and firsthand accounts of death on the battlefield that I wouldn't want a child in my care to see.