However, I don't want this to be boring! But so far, all i've got is:
1. Courtship: Introduce yourself, flirt, bring the character an item they like or escort them to a location they want to go (for example, one characters ideal first date might be a trip to the Yao Guai Tunnels!) One character, a ghoul to be specific, only lets people date his daughter {http://fallout.wikia.com/wiki/Born_ghoul} if they have Deadly Radiation Poisoning .
2. ????
3. Profit!
So, let me ask you: if you downloaded a mod that had some kind of a romance side-quest (which I want to be as unintrusive as possible- there'll be no relationship decay or anything like that, no pop-up messages saying "you should visit your girlfriend!" and things like six will probably be a fade-to-black kind of deal), how would you want it to be handled? Specifically, what would you envision as the whole point to dating an NPC to be? Would they just give you free items, or what?