So my friend and I drove all the way to find the blue one indicated here today: http://www.masseffect.com/space/SFO/

We were the last group left looking for it, and nobody was able to get it. The red one is apparently stuck on a cliff and has been determined unreachable.
The whole thing is kind of a wild goose chase. by the time you get anywhere near the landing site, all cell phone reception is gone, so its very difficult to get a map working or anything. Lots of thick brush, etc. Trying again tomorrow...