I saw a setting once for setting the chance a sim will leave the current lot & go visit a community lot, even if its active household. I cant find that now. Isn't it retuner who handles this kind of thing? If its elsewhere, please stop me now because I am losing sanity insisting that it is in there.

There may well be something reachable in Retuner for that, but I've never heard of it before. I believe what you are trying to remember is a function of StoryProgression.

On City Hall or an in-game computer, NRaas > SP > General Options > Options:Sims > Push Actives to Visit Lots > (default is 0, set percentage to something higher).
(SP Extra add-on module required)

I betcha thats it! We are so blessed with so many mods to help us manipulate this game that I have gotten their functions comingled. Great first world problem to have!