Yes they have plenty of seating for people who get tired. They also have an elevator to the different floors!
There is! Fonthill castle may be an issue if you want to go there as well but in every room of the tour there is a chair to sit down. Stair cases are narrow and steep many without great handrails but the mercer museum has an elevator and great seating with awesome views from those seats
Yes.
Elevators take you to different levels on the museum however you still need to watch your step. I have mobility issues. I took my time. There are handrails and I had arm assist from a friend when I needed it. The castle itself is dark and no rails . That may be difficult for some
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