Mount Stewart is nearby, also owned by the National Trust. This is a beautiful stately home (recently restored and now reopened to the public) and estate with a remarkable plant collection. There are lots of things to do for all age
The short ferry ride across the “narrows” either with a car or on foot is a memorable experience, and once across to the other side in Strangford, you can visit Castle Ward, a National Trust treasure.
There are lots of things to do there including visiting the historic mansion, having the “Game of Thrones” experience (this is one of the GOT locations), cycling or walking through the acres of beautiful grounds.
For those interested in natural history or who just enjoy a stroll through pretty countryside next to the sea, Castle Espie is a reserve owned by the Wildfowl and Wetlands Trust.
This is an internationally significant site for many wetland birds, including being an overwintering place for most of the world’s population of Pale Bellied Brent Geese.