Choose what you want from the outing
For greenery and a slower pace, make the park the main activity. For an architecture-focused outing, choose the Central Public Hall as a building of interest and leave time to look from public space that is open when you arrive.
If being indoors is essential, settle that part of the day before setting out. The ceramics museum's renovation closure changes the options; poor outdoor weather is a reason to choose another suitable indoor plan, not to assume a nearby building will admit walk-in visitors.