Hi Byrd,
You’re right : Because of your ‘location’ data is in subfield you can’t query post by using it as meta_query (to be honest you can but by using an ugly solution).
I had the same issue with a repeater subfield and I got a very helpfull advice from John Huebner : See my post here.
To resume : Use the ‘save_post’ filter on your event CPT to save with add_post_meta the location as simple metadata (For example : ‘wp_location’). Then you’ll be able to easily query it.
