Guide books covering the Danube on its last leg towards the Black Sea
Having good maps when cycling the area will be important. We recommend getting yourself the "Danube Bike Trail 4" and/or "Danube Bike Trail 5" guide book (by Esterbauer). They provide maps at a scale of 1:75,000 (and 1:100,000 resp.), route instructions and hints as well as lists of accommodations and camp sites along the cycle path.
In 2016 Cicerone publishing house expanded their "The Danube Cycleway" series now covering the Danube from Budapest to the Black Sea ("The Danube Cycleway Vol. 2). Maps come at a scale of 1:150,000 which is mostly sufficient as there are simply less roads and cycle path infrastructure.