Road trip routes
This trip is a short incursion south of the Danube, in Bulgaria. This especially because very close to the border there are some very nice places like Kanya Bunar canyon or Veliko Tarnovo.
The route is quite long so I recommend leaving Bucharest by latest 9am. If it's early spring or late in the autumn it would be good to leave even earlier becasue the day is short.
The road to Veliko Tarnovo is quite known especially for those who go often on holiday in Greece or Turkey, so my proposal is that you go on secondary roads through the Rusenski Lom area where you will find some beautiful places with deep canyons, some caves and a castle in Cherven. In Veliko Tarnovo you can visit the old town center and medieval fortress. Then you can visit Kaya Bunar canyon lies in the middle of a plane, a suddenly you will find a beautiful waterfall and a deep lake.