The Dupont Castle web site describes the castle as having 33 rooms, including one room holding a 1500 year old viking drinking vessel.
The American Swedish Institute further describes the castle as being an example of early 20th century chateauesque architecture.
Visiting hours are Tuesday, Thursday, Friday, Saturday 12-4 p.m., Wednesday 12-8 p.m., and Sunday 1-5 p.m. Admission is $6 for adults, $5 ages 62 and above, $4 ages 6-18 and full-time students with ID. Children under six are admitted free when accompanied by an ad
More information at the American Swedish Institute