Not all the items listed below may need to be on the one map. It is just as easy to obstruct communication by visual confusion. It may be preferable to have a master map and a number of derivative maps - one for the suppliers, one for the public and another for use on the Web. A number of outdoor events use an aerial map as the basis of this. It is not a neutral technique.
All maps are a summary.
Some things need to be left out and others highlighted. The wonder and ease of CAD can often obscure what it leaves out. There are no straight lines or perfect circles in Nature, and a map so created may not be a good communication tool. A hand drawn map with illustrations may be far better at communicating with your target audience than a precision CAD map. Also, an attractive, artful map may be used to set the mood for the event.