I'm seriously considering applying for an APEC Business Travel Card, and would like to use it for a Trans-Mongolian Railway journey, entering Russia by air at Irkutsk and China by train at the Mongolian border. (I'm aware that Mongolia is not in APEC and will be applying for a Mongolian visa separately.)
My understanding is that once endorsed, this is supposed to be valid for all business travel in APEC economies regardless of where you enter, but I've also heard mixed feedback about how well the card is recognized, particularly at more obscure points of entry like Zamyn-Üüd/Erenhot. I'm also a little worried about this being viewed more as tourism than business. Any references to official sources or practical experience regarding using the card at land crossings, and/or how to "prove" that this is business travel?