There are narrow corridors, passageways and stairs that are a challenge for regular walking.
As others indicated, there are stairs throughout the tour, many of them are uneven and are very narrow, sometimes don't a switch back in a very small space. The first floor is easier on a stroller but can still be problematic.
Not really. Maybe most places on the ground level, but not beyond.
Not everwhere. There are stairs at multiple spots, I don't think it has easy access to walk with stroller...
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