I've played them both.. Kawana in 2001 and Hirono this past February.. I was told at Hirono that they only get about 10 gaijin rounds a year and considering I was with some we took up some of those rounds..
Kawana is the bullet train to Atami station and then the local train to Ito and a short cab ride... I will say this about Japan, it is tough to travel without someone who speaks Japanese, the Japanese are very polite but I found there are few fluent in English enough for you to really get by. I was fortunate that one of my friends is Japanese but raised in Long Island.
Kobe is a great city to visit, the airport is pretty cool when you land on the island at Kansai. I would say Hirono is a good 40 minute drive from the city center and would be extremely difficult to find without a Japanese guide who knew where it was.