Just calculated my gearing...

I used to prefer gearing up for century rides on fixed (low 80s rather than high 60s).

• less revolutions
  
• less weight on rear (mine)
  
• easier to stand for a bit here and there
  
• less likely to bonk
  
  

In the end, it depends what average speed you're anticipating, and whether you're determined to ride up the steepest climb on the proposed route; and if you have specific training goals, these tend to override everything.