It was a very long time ago, early '80s, and to be honest, now that you ask me, I can't recall if it was my 250 CC dirt bike (Yamaha or Honda, I had a slightly bigger road bike at the time, one of each brand, not sure which was which) or my mates 750 (Honda I think). He had the power, but I had the traction, I've climbed up near vertical rock walls on it. It wasn't towed very far, just had to be moved several meters to the left, and no one had a car handy. It was the oversized caravan type mobile home. Wasn't moving fast enough to get enough momentum going to overcome friction when we cut it loose, it just ground to a stop fairly quickly.
Back to towing 313 kg of meth in a diplomatic bag, I have no idea how much space that occupies, so may need something bigger than a bike trailer. How big do they make diplomatic bags?