I'd try to keep tagging compatible with the EXIF tags related to position.
See the WIKI for some details.
Then you'll be able to combine your manual tagging with EXIF tags generated by an external utility such as Geosetter or Lightroom.
When importing image tags, MC populates the Places tag with the format CITY, STATE, COUNTRY.
So, for your manual work in MC, tag Places according to the following format: CITY, STATE, COUNTRY.
I don't remember the name just now but there is a fourth tag in exif, sublocation. Usually, this EXIF tag is populated with street name/adress but I have seen other location types. Use this to for Opera/Railway, etc. you may have to make a library field
Then you can make a calculated field for display which replaces the commas in the MC Places tag with slashes and adds sublocation.
Your view scheme would then be able to support both your manual tags and tags generated by external apps.
(There have been requests in the past to expose CITY, STATE, COUNTRY, SUBLOCATION as MC fields, btw)