Are the tours at certain times only or can you just show up? Do you have to do a tour or can you just tour on your own?

Typically at the top of the hour.

The tour of the home is available all day 9:00-4:00 and can only be seen with a guide, however you may explore the grounds freely, by using the walking trail and playground.

You can go anytime during the day, the tours are given as wanted

They are scheduled during the day.