[Book/TV Spoilers] Myrcella's route

[pavel]

Hello fellas. Been reading those forums for a while and I figured I'd start contributing a bit. I hope this hasn't already been covered!

Watching episode 6 got me to question Tyrion's plan to bring Myrcella to safety. I don't have my book 2 so I couldn't reread anything to double check, but with a bit of research I found out the boat on which Myrcella sails actually heads to Braavos first, and then heads to Dorne.

I was seriously questioning Tyrion's decision of having his little princess sail a long distance in ennemy territory (ie waters controlled by Stannis) but now it makes more sense. However, sailing from King's Landing to Braavos does appear to require getting somewhat close to Dragonstone. Do the books every explain the route taken? What makes Tyrion believe she won't run into trouble? We all know Stannis' whole fleet gets to King's Landing pretty soon, and Tyrion knows it as well, but does he have any information that lead him to believe Myrcella has time to get out of harm's way?

We know Stannis' last known location is around Storm's End after Renly's death, so most of his fleet must be there, but that doesn't eliminate the risk of some ships patrolling near Dragonstone.

As for alternative routes, the only other choice would be making the trip on horse, which would probably require squeezing between the Stormlands and Tyrell territory. Seems hazardous when you consider the Tyrell haven't declared for anyone yet.

I'm no sailor so I may have missed something, so comments and precisions are appreciated!