Strada Provinciale 19
Biking around LazioNot as famous as Tuscany or Umbria, the Lazio region (which includes Rome) is nevertheless gorgeous with scenic rolling hills.
I took the above picture while biking between Grotte S. Stefano and Sippicciano. It was mid-October, with highs right at 70 and lows in the 50s. Perfect biking weather.
One thing to avoid is the hour or so after it stops raining. Huge swarms of gnats make for face-bug-swatting.