Michael I responded to your comment on another post, but essentially I think you're right in that it can be tricky but that there are opportunities. Be sure to take a look through the  discussions to see what others are thinking about. Proxy data like you mentioned is a GREAT resource and there are certainly places where you can get your hands on what you need. Pat Harcourt, who is also one of the facilitators of this course, is well-versed in resources for proxy data and I think she will be talking about it specifically during one of the evenings.