However, I ran into a little snag while editing and publishing everything. The problem was that each photo’s GPS/location data wasn’t making the jump to Flickr from Aperture. The solution was these two check boxes that needed to be selected in order for the location info to be correctly exported: one in Advanced Options and another in Export Preferences.
So in the end, if you make sure “Include location information for published photos” and “Include location info in exported photos” are both selected, everything works beautifully.
Aperture Places view
Flickr Map view