Rose,
Based on these articles, it looks like Thornhill farms was just a staging area, not a potential site area. Thornhill serves the community with organic fruit and veggies...and they offer 'horticultural therapy' for disabled teens in the area.
While they don't appear to have any connection to this case, outside of having enough room and grounds to host all of the searchers, I do think it's interesting that this place works with teens from local high schools. While they are disabled, they are capable of doing farm work---which is seriously difficult work--so it seems possible that one or more of them COULD have driven a vehicle or harmed Brittanee. That being said, I really think this is just the staging area, and I sincerely hope this has NO connection to the teens working this farm.
It looks like THIS search was for the month following Brittanee's disappearance...in may, not december. I'm still looking for a later search and staging site for december...but I really believe this is the exact area they are focusing on!! Wish we could find that dock. During the first few searches, LE seemed split between the Frances Marion forest area and N Santee River. In December and again in January, they moved to a more specific area in and around the N Santee River....based on all of the new tips. Remember, Originally Brittanee's phone was pinged to the South Santee area, which would be very near Frances Marion Forest. I think her phone is in a different location than she is.
http://www.live5news.com/global/Story.asp?s=10325820
http://www.wmbfnews.com/global/Story.asp?s=10327696