Interview for TD

[northstar]

I am currently holding a TN visa status, My wife has become a canadian PR, however she is not in canada right now. I wanted to apply for TD visa for her. I wanted to know if I must go to for an appointment with U.S consulate in canada for TD or Is there a way if i can just fill a TD application and then send it to embassy, it would save me the hassle of going to Canada first.

do you thing is it viable to just send the application?