Fine dining? Try the Saint-Amour, within the walls of the Old City. I had some spectacular fare there a few years ago - around $100 per person foran everything-in dinner. This summer I had a less expensive, delicious rustic meal of locally sourced meats and veg that at the Restaurant Sous Le Fort near Place Royale, down below the Chateau Frontenac. Very good despite the touristyness of the area, and in a wonderfully old, charming building.
Avoid the tour of the Frontenac, led by turn-of-the-century costumed guides, unless you can handle the sugary sweetness of the tour's tone. It's one of those '"we're all pretending it's 100 years ago" type things. Ick. Walk the halls of the building on its own however - wow!
If you have a car when you're there, take a half day (or more) and head out for a round-the-island tour of Ile d'Orleans just to the east of the city in the Saint Lawrence River. Gorgeous, with lots of artisanal food producers to stop into.
If you don't have time for Ile d'Orleans or no car, make sure you walk not just the Dufferin Terrace, but the walkways suspended over the wooded cliffs surrounding the Citadel. Stunning views! I think they open up best when started at the west end, so approach from the Plaines of Abraham end. Maybe a visit to the Citadel first?
Anyway, it's such a beautiful city - have a great time!
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