Headed to Asia with my wife for 3 weeks and we would appreciate any recommendations! For context, we are very active/outdoorsy people, want to get see some history, have a lower attention span for museums (although we'd still like to see them), and hope to have some authentic cultural experiences as well as normal tourist spots.

Taiwan (Taipei for 4 full days): We will be staying in Da'an district in Taipei. Will be spending 1-2 days with friend who lives here. He's taking us to the Symphony and not sure what else! Other things we're thinking about are Yangmingshan, night markets, museums, sports etc.

Vietnam (2 days each in Hanoi, Ninh Binh, Mai Chau): Considering Ha long bay but would be a long day trip from Hanoi. Aside from that, we're just excited for kayaking, hiking, and other nature stuff.

South Korea (half day): We arrive 5am to ICN and have departing flight at 7:30pm. Hoping to see Seoul in a day and eat some good food.

Japan (4 days in Kyoto, 1.5 Hiroshima, 3.5 Tokyo): No concrete plans aside from where we're staying. Any suggestions on day trips from these areas, things that are over/underrated etc. would be appreciated.

Thanks for your help!