I have had issues with these crawled properties not being mapped correctly to Managed Properties by default. In Site Administration > Search Schema, this is what I have done:
RefinableDate01 – This is a SharePoint provided Managed Property of Type = Date that is provided for configuration. It should be mapped to the Crawled Properties: “ows_q_DATE_EventDate” and “ows_EventDate”. This is the Start Date field in a Calendar.
RefinableDate02 - This is another SharePoint provided Managed Property of Type = Date that is provided for configuration. It should be mapped to the Crawled Properties: “ows_q_DATE_EndDate” and “ows_EndDate”. This is the End Date field in a Calendar.
My guess is that you could do the same for Location. Also make sure that the calendar has been re-indexed after you do your search configuration. I have had to go back into the calendar list settings and under Advanced Settings > Reindex List if the list items have been out there for awhile and are not getting indexed.