and if I come from Italy, which is the best route?
The fastest option is to go trough Switzerland and Germany, but in Switzerland you need a vignette. The other option is to go trough France and then Germany, but in France are some toll ways.
and if I come from Italy, which is the best route?
I don't know where in Italy you live. My family lives near Venezia. We ride from Bolzano - Brennero - Insbruck - Munchen - Nurnberg - Frankfurt (Francoforto) - Oberhaussen -Enschede to Hengelo.