Howdy,
I'm an American permanently trapped in Japan (except for this second I've visiting home in Atlanta) and found your site while Googling Japanese theme parks.
I totally dug your Nasu Highland pictures, which my friends and I dubbed "Ghettoland" upon out May visit. It's amazing how smoothly the place runs even when no one's there.
Did you guys hit the haunted house dark ride at the park? It was closed when I was there, but it has a good rep and I'd love to see some photos if you have any. And how can you go without posting a shot of "Hell Ship?" I'm sure the "River Adventure" was closed in the snow, but it's pretty lame and does not have an acceptable level of wetness.
Next time you make it out there, you'll have to take a ride on the SLC. It's a little more painful than the other coasters (well, except for maybe "Panic Drive") but it's got good airtime.
All aboard the "Hell Ship!"