Among Japan's major jitenshado, or bikepaths, Shimanami may take the prize for the one with the most spectacular scenery. But when it comes to the prize for most centrally located bikepath leading to the most major tourist destinations, it's not even a contest. Millions of tourists visit Kyoto and Nara each year, but it seems that only a tiny fraction know that it is possible to travel the 50-km distance between the two ancient capitals almost entirely by bikepath. On the car-choked regular roads, this would be a most unpleasant trip even by car; by bicycle, on a quiet route through the greenery beside the Katsura and Kizu Rivers, it's pure pleasure.
This route actually consists of two bikepaths linked by a short section of ordinary road. By far the longer bikepath is the Kyoto-Hachiman-Kizu Jitenshado, so named because it goes past Hachiman to Kizu, just north of Nara. The route actually starts at Arashiyama, a popular tourist destination west of Kyoto proper. After 45 kilometers of almost completely level cycling, the bikepath dumps you out not far from Kizu Station, where you're unfortunately obliged to go onto the regular road. However, sidewalks allow you to avoid the horrendous traffic... and after about two kilometers, you can hook up with the second, shorter bikepath that will take you all the way into downtown Nara.
Although it's a pleasant trip, there are few sights of any consequence along the way - so save your sightseeing for the ancient capitals and use this route as a great way to get from one to the other.