In the morning, visit the War Remnants Museum to learn about Vietnam's history. In the afternoon, explore the Notre-Dame Cathedral Basilica of Saigon and the Central Post Office. Spend the evening at the Saigon Opera House and enjoy a cultural performance.
Take a morning flight to Da Nang and drive to Hoi An. Visit the Hoi An Ancient Town, a UNESCO World Heritage Site, and take a boat ride along the Thu Bon River. In the evening, attend a lantern festival and enjoy the beautiful lights.
Visit the Imperial City of Hue, a UNESCO World Heritage Site, in the morning. In the afternoon, explore the Thien Mu Pagoda and take a boat trip along the Perfume River. Spend the evening at the Dong Ba Market and try local street food.
Take a morning flight to Hanoi and drive to Halong Bay. Take a cruise and visit the limestone caves and fishing villages. Spend the evening watching the sunset on the bay.
Visit the Ho Chi Minh Mausoleum and the One Pillar Pagoda in the morning. In the afternoon, explore the Old Quarter and the Temple of Literature. Spend the evening at the Thang Long Water Puppet Theatre and enjoy a traditional performance.
Take a morning drive to Sapa and visit the rice terraces and ethnic villages. In the evening, relax at a hot spring and enjoy a massage. Spend the night at a homestay and experience the local culture.
Other local attractions to consider are the Cu Chi Tunnels and Mekong Delta in Ho Chi Minh City, the Marble Mountains in Da Nang, and the Hoa Lu Ancient Capital in Ninh Binh. You could also take a side trip to Phu Quoc Island or Nha Trang for some beach time. To maximize your fun, try learning some Vietnamese phrases and try the local cuisine. Don't forget to bargain when shopping at the markets. Enjoy your honeymoon!