Old cities are best read at street level: worn steps, open shutters, the smell of coffee drifting out before the door opens.
One anchor per day
Book a museum for Saturday and a long lunch for Sunday. Between them, follow streets that look interesting. A single fixed point gives the day shape without closing it down.
Visit the market early, when it still belongs to the neighborhood. Return to the central square after dark, when the day visitors have left.
Do less, look longer, and let the same street surprise you twice.