Dominicanen bookshop
Go for the former church interior and stay to browse. The shelves sit beneath the vaults, and the café occupies the choir. It is centrally placed between Markt and Vrijthof, so it fits almost any first-day route without a detour.
A short visit can take half an hour; readers can easily spend longer. These are planning estimates, not timed tickets. If the café is full, you can still enjoy the building and find a table elsewhere afterwards.
The shop's own access information describes a lift in the book structure and facilities for wheelchair users. Check it before your visit if that affects your route. Address: Dominicanerkerkstraat 1.
Coffee in the choir
The café occupies the former choir, with the vaults overhead. If you are visiting with someone who wants longer among the shelves, it is an obvious place to meet afterwards.
Keep the main aisles clear when taking photographs. This remains a bookshop, and the mix of readers, café customers and visitors is part of the experience.
Build it into a central walk
Start at Markt, visit Dominicanen, then continue to Vrijthof. From there you can go south towards the Jekerkwartier or west along Brusselsestraat for an evening drink.
For a rainy afternoon, pair the bookshop with a meal in the centre. If you want a longer indoor visit, choose a museum as the main event rather than expecting the bookshop to occupy the whole day.