As I mentioned recently, Shikoku is an island filled with mountains. It's a pretty hot, humid place, and the isolated nature has left nature isolated. A wide variety of buildings have been used historically around the island given different climates, needs, flora, and fauna. Many of them have been preserved or recreated here.
This is a very well done outdoor museum with excellent English signage and fairly-unique structures. It's a pleasant location and certainly worth the time and effort for those interested in architecture or Shikoku's history.
Up Yashima mountain, behind the park, are some attractions including a monument, viewpoints, a temple, and a small aquarium. Yashima can be reached by the once-hourly shuttle bus from JR and Kotoden Yashima stations.
Access is possible by JR lines, using Yashima Station (15 minutes plus 15 minute walk, about 2 trains per hour), but Kotoden Yashima Station is closer (about 20 minutes plus 5 minute walk). The Kotoden line takes longer and costs more, including a transfer of trains; trains on the second leg of the journey run about three times per hour.
The park is open 8:30-17:30 (18:00 April-October) and admission is 800 yen (1000 yen including the art gallery).