I don't have as clear a picture in my mind as when I was actually working on this stuff, but I remember giving up for reasons similar to what I described.
A long term goal of mine was to make a sort of cross between Homeworld and Jagged Alliance 2. E.g. an RPG-lite where you have a grid of sectors to control, roving bands enemies, as well as NPCs, quests, phat lewt, etc.
Not sure how far I will ever get, because designing an singleplayer campaign from scratch is very daunting.
I did get a basic conversation/dialogue system working. And you can technically rove around between sectors except for the problems I've been describing.