Why was Dragon in Loguetown at that time?

[Warmmedown]

1. Was he there to watch Luffy leave for the Grand Line? If so, was he planning on meeting him, or just watching him? Or was he there for some other reason, related to the Rev Army?
2. How did he know Luffy was going to be at Loguetown at that time? Did he have someone watching Luffy? Or did he just find out about Luffy's bounty and figure he'd be at Loguetown soon? Or is Dragon able to travel very quickly somehow? Maybe he's able to cross the Calm Belt, like the marines can, if can control the wind or sea somehow, has very strong CoC to repel sea kings, or can maybe even communicate with them like Luffy can. Or maybe he can travel in the sky.

 

[SSJ2]

I'm guessing he saw Luffy's exploits in East Blue and knew that he'd be making his way to the Grand Line soon. And being a former marine and with his intel, he knows there is a Logia marine captain there who would be impossible for him to beat.

He can definitely cross the Calm Belt one way or another, Old Rayleigh swam through it with ease.