Svojanov Castle towers above the valley of the Křetínky River on the Bohemian-Moravian border and is one of the oldest royal castles in the Czech Republic. It is unique in that medieval Gothic meets early 19th century Empire, so you can see two completely different eras in one complex. On site, you can choose from guided tours that take you into the interior and exterior of the castle.
With a stroller, the path to the castle is easily navigable and the stretch from the car park to the entrance gate is mostly flat, plus circuits A and C are stroller-friendly.
Just allow for the fact that some parts of the castle and selected tours may be more challenging due to steps and rough terrain.