We took 3 Koreans (2 adults and a child) to see the museum in December. The weather was fine- which helped, of course.
However, the number of buildings to visit was prodigious so even if it had been less fine, we'd have had a good time. If wet, though, an umbrela would be essential as the various "components" are widely spread out.
I can best characterise the site as a small hamlet in the country, with a couple of farms, woodland- including woodland industry-and a mill with its millpond around it. Several buildings have electronic commentaries; others have guides who tell you about things- who lived there, what sort of things they did and so on.
Being able to see contrasts -for example one cottage was half 15th C and half 18th C- made it more interesting.
Good refreshment room -we sat outside and picknicked.
Plenty of restrooms.
We spent about 3.5 hours there, and didn't do everything.