May 15-31 Mon-Fri 9 am - 3 pm, Sat-Sun 11 am - 5 pm June 1 to August 31 Mon-Sun 11 am - 5 pm September 1-15 Mon-Fri 9 am - 3 pm, Sat-Sun 11 am - 5 pm

I believe it is staffed in the busier summer season and then the buildings are open to enter as well. But when I went in April there were no dressed up people and no entrance fee.

Ninguno

In addition to the signs at each place, there are also guides at some of the more popular spots who can answer questions. I don't think a guided tour is necessary.

The island is accessible year round, however the museums inside the buildings are open only during summer i.e. May to End of September.

The bus 24 will tke yiu very close to it. You can use Google Maps on your phone to plan your trip as it gives you public transit directions also.

The 24 Bus is included in the day ticket, as it's route remains entirely in Helsinki. As other reviewers have pointed out, the "regional" fare only kicks in if you head out of the city. For visitors, the two most likely reasons you'd need a "regional" fare is if you were visiting the nearby city of Espoo, or heading to the airport which is actually in the city of Vantaa. As long as your'e inside Helsinki, a standard ticket will work fine, and Seurasaari is inside of Helsinki's borders (although just). The Helsinki trams are all covered by a typical day ticket as well.