The Danube

Shortest, easiest acces to the source.

From the official source in Donaueschingen and the Zussamenfluss ... much of it on good dedicated track.

Leading to the Romania side of the Iron Gates ... and so to Drobetu ... to cross back into Serbia ... and so into Bulgaria. Alternatively cross back to the S bank at Ram to take the Serbian route into Bulgaria.

Careful map-reading required to avoid (repeated) crossing into (and out of ) Croatia. Stiff climb (on good road!) approaching the Iron Gates.

In 2015 accommodation was scarce between Drobetu and T Magurele; the southern route through Bulgaria offered more. However the stretch beyond T Magurele was said to be impassable after rain.There are a few ferries to chose from before then. The stretch to the delta avoids Cernavoda where there is s…

Taking the coastal route into the delta to the furthest point east that is accessible by bike ... and back to Tulcea (for the the train). (In 2015 Sulina was only accessible by boat.)

This route is based on Including the Breg (+58km on separate map) My experience of 2012 Taking in a few places I missed on the other bank in 2012 A 5-week window ... therefore the easiest options.