SimonB, Also, I subscribe to Blue Water Sailing and their companion site, wwwcrusingcompass.com is sent to me by email all the time.
Here is a good cruising site that is also Emailed to me. http://www.latitude38.com/lectronic/LectronicLat.lasso
The Rio Duce has interested me and some of my crusing friends have done that trip. If I remember right you have to cross a bar when coming in from the sea and that can be hairy. Also, up in the Lake they have fresh water sharks. The people are very friendly although there was an incident about a year ago. Maybe someday.