That is a great idea.

Do gmail accounts "time out" if you don't have activity or visit them often enough? I have a yahoo mail account that keeps timing out on me.

I think the registration site had a field in which you could put any related information. Another possibility would be to just access the registration site and enter the user's information and even trip specifics. The fact that I can go into the site and modify it at any time is pretty powerful. The one extra thing that might be nice would be the ability to attach a few documents (trip plans, maps, etc...).

Ironically the registration site is down right now.