Vietnam offers many great places for cycling. It is possible for you to find suitable places for both easy countryside cycle and mountain biking.
If you are interested in easy cycle, I suggest cycling in and around Hanoi, cycling in Hoa Lu, Kenh Ga and Tam Coc, Ninh Binh province. These areas are flat and easy to cycle. The scenery is quite beautiful with karst mountains, countryside villages and immense rice fields. The biking tours are short including half-day, one-day and two-day tours.
For more challenging cycle tours, I recommend other cycle route such as Ha Giang, Cao Bang, Sapa, Lai Chau…These provinces are located in northern Vietnam offering beautiful landscape and rich culture, traditions. You will also have the opportunity to meet friendly local hill tribe people along the cycle route. These tours are longer and sometimes need your training.
There are also lots of other cycle route in central Vietnam and southern Vietnam such as Hue, Hoian, Nha Trang, Da Lat and the Mekong delta.
We can’t say which one is the best cycle route. The best cycle route will depend on your needs and interest.