Southern Taiwan offers the best of both worlds. It has the modern features
Southern Taiwan
Taitung County
Just south of Ilan is Taitung County, one of the most underdeveloped parts of Taiwan. This is the place to go if you want to see undeveloped beaches. One site worth visiting is the Cave of the Eight Immortals. Just north of Taitung city, these ancient caves carved out by the sea are now brightly colored temples and shrines. Nearby is the Platform of the Three Immortals, although there isn't as much to see there.
Taitung itself is rapidly growing and the local government is pushing hard for tourist dollars. There are currently parks, museums, temples and other environmental attractions to interest the unhurried traveller. Southwest of Taitung are the hot-spring resorts of Chihpen. Chihpen has it shares of luxury resorts and bad traffic, but there are plenty of hiking trails that will lead you away to the more tranquil countryside. Most of the hot-springs are controlled by the big hotels, but the local waterfalls and the Chihpen Forest Recreation Area are certainly worth visiting.