As a couple, Český Krumlov Day-Trip works.
Possibly the most photogenic small town in Central Europe — a castle, a river loop, cobbled lanes and a painted tower that look unreal from the overlook. The honest catch: it's a long 2.5–3 hour each-way haul that makes a day-trip rushed, and by midday it's so tour-packed the magic thins. It rewards an overnight far more than a same-day dash.