@Ulrich: In Mexico you may say: "A ver cuándo nos vemos. Que te
vaya (muy) bien", with no linking word --unless you're writing a rather formal letter.
"Que te vaya bien" or "que estés bien" are colloquial expressions to say good-bye to someone and at the same time wish them well.
Also, "a ver cuándo nos vemos" is a way to express that you'd like to see the other person in the near future, but you're uncertain about the circumstances or the dates. This normally implies that you're either leaving it to a random meeting or that you both will communicate to agree on an appointment.
Although this may be used as a polite way of delaying an unwanted meeting, it normally expresses a true intention to see each other again.
