Google translates it to:Contact sera etabli lorsque vous serez a destination. Prenez bon soin d'elle. J'espere que vos yeux ne vous causent pas de peine.
Yea I agree with your interpretation:Contact will be established when you are has destination. Take good care of it. I hope that your eyes do not cause you sorrow.
"vous serez a destination" = "you are has destination" should be "you are at destination"
d'elle = of it should be of her
paine = sorrow should be pain
The girl is probably the one he was holding hostage (who doesn't want to talk to him). I think the title, "crossing the bridge" may suggest he's going back to America.
Eyes causing pain is what this cipher did to me.