From Osaka's Kansai Airport, take the JR line to Hineno Station in Wakayma prefecture, where you can transfer to an express train to head for KiiTanabe Station in Tanabe City. Local Ryujin buses run from KiiTanabe station to Takijiri-oji.
The bus will continue along major locations on the Nakahechi route from KiiTanabe Station to Hosshinmon-oji (through Kumano Hongu Taisha). More local bus information can be found here.
Accommodation and transportation can be booked in advance through Tanabe City's tourism website.
The tourism office acts as a community-based travel agent who bridges communication between local businesses -- normally run by non-English speakers -- and international travelers.
More resources can be found on Wakayama's Kumano tourism website.