From Hanoi there is a number of motorbike day trips can be reached within a few hours meaning that you can do them in 1 day and return to Hanoi or stay there overnight.
Ninh Binh is a city 100km south of Hanoi. It has many large temples but it is most famous for the boat tours with the rivers and limestone mountains. When taking a motorbike ride through Ninh Binh you can also see the Incense Village, at Quang Phu Cau, with many beautiful colours. There is the Perfume Pagoda which you can reach via a boat ride then a climb or cable car up the mountain. In Ninh Binh itself there is the large Bai Dinh Pagoda, the small Bich Dong Pagoda, the stunning view from the Hang Mua Viewpoint and the boat tours at both Trang An and Tam Coc.
The map below shows 2 routes to Ninh Binh from Hanoi. The Eastern route is easiest ride for getting out and in of Hanoi but if you want to see the Incense Village or Perfume Pagoda then the Western route takes you past these.
Ba Vi National Park
Just 60km West of Hanoi is the Ba Vi National Park. The national park is situated at the top of a hill with a view all around. On a clear day you can see Ba Vi from Hanoi. Within the park there is a lovely drive to the top where you can park to enjoy the view but also walk up further to see the Uncle Ho Temple. There is also the ruins of the French era Church you can see on the way up.
On a warm day you can stop at the natural swimming pool which redirects water from a nearby waterfall. The pool has many slides and is well worth a visit.
The map below shows a quieter ride to reach Ba Vi by following the river North of Hanoi until Son Tay then heading to Ba Vi National Park.
For longer trips in the North you can see the link below. Which has more options for longer routes.