So, here is the story. I sent some cards out, and as I have a 'lower rating' than most people (just found out about this site a month ago) I agreed to send the card out first. As they are only going from Kansas to Chicago (and not the moon) it would be reasonable to assume that it should have gotten there in 3-5 days.

Well, it's been 9 days (mailed out on the 11th, today is the 20th), and not only is the guy not really communicating at all, but he hasn't marked the card as received, nor has he sent out the card that I was to receive? What course of action should I take? I hate to open a BTR for one card, but... I don't even want to bring up a BTR with him, as it might come off as pushy or rude.

Advice?

My advice: always use tracking to avoid this type of situation.

However, the rules state 2 weeks as the amount of time you must give for regular mail. After 2 weeks, ask in chat if he's gotten anything. If no response after a day or two, email him directly (via the link on his profile). After that, then feel free to open a BTR.

Sometimes the mail is slow. I've had it happen a couple times where my stuff takes longer than normal. But to avoid any stress, use tracking in the future. It costs more to ship, but its worth it to avoid the stress/hassle of knowing whether or not they got the cards.