Check out the "training tips" page on my blog for some thoughts. Also, go to youtube and do a search for "Julie Slater trailer loading."

Your horse doesn't TRULY lead/listen well. She needs some ground work to help fix this.

Other's above have addressed it and it all comes down to the same thing. Fix the hole in the ground work and she will go where you tell her.

Riding Blog: www.spottedtridingblog.com  

For those looking to track their riding and needing a nudge to get in the saddle, check out the Spotted T Ride Program.