Lets just keep it simple. For those that use this we can stick with it, but like you said others might not see it all the time.
I think it would be easiest to organize on here, but if some people would like to get notified by email that were trying to plan something, it can simply be an email stating were trying to get together, go to the forum and give your input.
Trying to set up something up through emails with a couple people would be a nightmare. At least here everyone can see everyone's responses and go from there.