Recently a friend of mine asked me how to do a key plan in Revit, I thought about it and decided that because Revit doesn't currently have any key plan capabilities, the best option would be to create a detail component that is placed into a legend.
1. Export your plan to a DWG file
2. Create a Metric Detail Component. File > New > Family > Metric Detail Component.rft
3. Import your DWG file.
4. Add a Yes/No Parameter for each area. Types > Add Parameters > Type Yes/No. Set this as an Instance Parameter and give the area or filled region type a name.
You now need to add this parameter to your filled regions, once a filled region is drawn, go to the instance properties, and under the graphics title, select the = symbol at the right hand side of the word visible, this will allow you to associate a family parameter with this type of shade, select a name from the list and click ok.
5. Now you can load this Detail Component into your project and create a new legend view that will be called key plan (or something similar to suit your requirements) place this detail component into the legend view, and manipulate the yes / no parameters as required in the family files element properties.
There you have it, a simple work around for key plans in Revit.