You can rotate by season as you are or by so many days. I play all households witch is quit a lot and so rotate faster by braking my week down. I play each household 2 sim days, as in mon/tue - wed/thur - then do three day weekend fri/sat/sun. That way I am not stuck on any one family too long since I have so many. As for keeping track; I do keep index cards on each family with names and things like aspiration, jobs, hobbies, and who they are liking. Keeping up with the story is easy in sims 2 unlike 3 and 4, in that they have the great in game picture and story book. (sorry don't know what it is called). Love it and take lots of pics and writing my story there as it goes along. Then if I don't remember what is going on last in a family I come back to, I just check the story album to refresh my memory and go from there. The Sims 2 is the best and this story album is one of the big reasons for me.
I hope you enjoy you new game play style what ever it is.