Yeah, tilt trailer. Un-tilt it, ride right on, and your weight pushes the front down into the lock. It's not even a wild ride
You can even do 2 at once. Just make sure the first guy rides on to just short of pushing the front down, and stop and wait there until the 2nd guy rides on. I can't think of a way to make it easy for 1 guy to do 2 bikes, though.
Triple axels, that thing is a monster C! What did you say you were towing it with?