I'm glad Barb chimed in. She's the person that I was talking about in the my post above. Another thing that seemed to work well on her ride was having cell communication (in her helmet). I'd ridden much of the route she used for her 1,000 a few weeks before her attempt. I went much
more slowly! I was able to follow along on her ride and act as a sort of "mission control." It can be difficult to fiddle with GPS buttons while one is riding. From time to time she'd report in and ask how far she was from a certain check-point. I could plug the info into my mapping software and give her answers, as well as point out potential difficulties along the way.
We found out that it is a bad idea while in Canada to give directions to "The Tim Horton's in Cornwall", for example. It's really necessary to specify which of the eight locations.