Aowanda is gorgeous and by the time you go there in a month the maples will be turning red and just the drive down from Wushe is worthwhile. You can stay in cabins and eat in the cafeteria which has surprisingly good food if a little salty (aboriginal style cooking). Also, there are supposedly two natural hotsprings rather remotely set in the mountains. Nice place to relax and do a bit of light hiking. The park headquarters have some English info.
recreate.forest.gov.tw/forest.ph … n&forest=4
The website is for Aowanda. Seems you can get a bus from Puli though there have been so many changes to bus schedules this year make sure you get someone to confirm all this. The new Lonely Planet, which will be out this month, unfortunately does not mention anything about Aowanda and Chingjing Farm. No space left for Aowanda, and when I was researching Chingjing I was fogged in for two days.
Chingjing is beautiful to drive through and stop for a coffee in a heavenly in some picture perfect alpine setting but unless you are doing it by car I wouldn’t bother. Same with Aowanda. If you want to see the area rent a car in Taichung. Traffic is light this time of year so you shouldn’t have any troubles. If you have any interest in Buddhism drop by the amazing Chung Tai Chan Temple in Puli on your way to Aowanda. Temples tours are in English.
if you are heading to Aowanda make sure someone calls for you to inquire about the road conditions. Lots of areas are in a mess after a summer of earthquakes and typhoons.
Why on earth would your friends want to go to Kaohsiung? Give it a miss and visit Tainan or head inland to Meinong and Maolin national park.
Yilan has several beaches, Taipingshan, and the National Center for Traditional Arts if you have an interest in taiwanese arts and crafts. Lots of beautiful mountains and rivers to explore if you have a car or scooter.