I'm not sure how they would get behind the Trading Post to build unless they went through the the 100 loop or possibly made a road between 200 and 300 and came around the back by the creek.
Remember, the plans that are going around again are from 8 years ago and don't even show the new stable plans that have recently shown up. It wouldn't surprise me if the 8 year old plans were enough out of date to not reflect what they may actually build.
j