Assuming you can handle an uphill or two (hundred), this is a near-perfect combination of cycling and culture: straight south from downtown Osaka (or nearer if you prefer) and up to Koya-san, name of both the mountain and the mountaintop Shingon Buddhist temple community for which it is famous. Koya-san (elevation 850m) features more than a hundred temples – in the old days, it was nine thousand! – and a long cemetery (the Okuno-in) so enormous that one travel writer dubbed it the "Necropolis." It doesn't make sense to come all the way here and then not allow plenty of time to see everything, so the trip is best done in three days: one day to get there, one full day to explore everything there is to see at Koya-san, and then a third day to cycle the Koya Skyline (up to 1,372m elevation) and then enjoy a long, long downhill to Tanabe, a seacoast city in Wakayama that is also a stone's throw away from Shirahama, arguably the most popular beach - and - hot - springs resort in the Kansai region. Each of the three days will be different, offering its own special attractions. Day One provides the chance to make a brief stop at Kawachi-Nagano, a pretty rural part of Osaka Prefecture that hasn’t yet made it onto most tourist itineraries. On Day Two, you can eat "shojin-ryori" (traditional Buddhist vegetarian cuisine) and start the day out with a traditional Buddhist prayer service early in the morning at your "shukubo" or temple lodgings (practically the only type of accommodations available at Koya-san). And on Day Three, you can tackle the Koya Skyline and then enjoy a long downhill, pausing to rinse away the perspiration at Ryujin Onsen, one of Kansai's most famous hot springs, or at the aforementioned beach resort and onsen. In my opinion, this is one of the better three-day trips Japan has to offer.