How to map different entity types as layers with OpenLayers? My implementation requires the mapping of multiple entity types, which is difficult to achieve in vanilla Gmap with Views. 

In the documentation, OpenLayers states that layers can produced from views of OpenLayers data type. Is it really as simple as specifying a few layer views and adding them to a map?

If so, and multiple views can be served as data sources to OpenLayers, what does one have to do to convert a Location/Gmap set up to OpenLayers?
So, OpenLayers requires Geofield as a spatial data format, which is better than the Location Module for spatial formats. There's no simple solution to convert the data, so you spatial content will have be updates with Address or Geofield formatted data. I used Views CSV export and Feeds to dump and spit back the data to the right fields. From there, I followed the tutorial here Multiple Layer Maps with OpenLayers creating multiple data overlay views to a build a map based on layers of different views. This let me overlay my users over my other spatial nodes.