I'll be in Japan on business in early June.  I'll only have 1 day (probably only half a day, really), to do 'sight-seeing'.  For me, that'll be riding some coasters.  I'm up for traveling an hour or 2 away if I need to.  Fuji-Q Highlands would be my first choice, but it seems to be about 3 hours from Tokyo, by train.  I'm leaning towards LaQua so I can ride Thunder Dolphin.  Is there something I'm overlooking; a park that I should be going to instead?   
  
Thanks in advance. 
  
Any other non-coaster related Japan advice?  I'm pretty terrified of the culture shock, and not looking forward to a 16 hour flight.