Some more details on the trip:
Potsdam to Wittenberg: The R1 trail was remarably well paved; we followed it out of town through the spectacular Park Sanssouci and into a succession of agricultural fields, woodlands, and cool tiny towns. Throughout, the trail was perfectly smooth concrete! German engineering at its finest. The R1 trail continues past the German border on either side, too, to link up Calais, in France, with St. Petersburg, in Russia!
The way was hot and sunny for the most part; very few clouds. Camping was typically civilized, German style: kitchen buildings and showers complement small tent plots.
The beer is incredibly cheap in Germany (and very good). We would daily enjoy a couple of 0.5 litre bottles of pilsener for around 50 cents Canadian! Beer o´clock, for Germans, seemed to start at around 10 a.m.; this time was subsequently smashed in the Czech Republic who pulled into our campground and cracked beers at about 7 a.m.
After a few hundred km of cycling and two nights on the R1 trail, we refueled with some real food in Wittenberg and checked out the old town, with its open moat running through the cobble streets. From here, we also planned the next stage of the cycling, along the Elbe River trails that lead to Prague.