My predilections see a Gazetteer as the main common element, the organizing backbone. Some entities (cities, most notably) are lat/long points; others (like countries, provinces) are polygons.
Microsoft Access has the advantage of being available and known, and easily extended, and accessible via forms-based web pages for queries and new entries.
This is fundamentally the territory being explored by Frank Settle's Bomb Project, and much of the basic organization should be adaptable to David's needs. It just can't be that difficult --and if we can do it once, we can replicate for other uses and users.
log on Miley (it may be confusing to have both, but it seems worthwhile to have some sort of documentation in the directory where the Access stuff is happening).