Cathe often doesn't visit the forums actively (she might just have time to do her moderator duties). She's definitely not 'around' much when filming, and often when planning some venture (like the calendar?).
Or, like you suggest, maybe she just needs some down time and is spending more time with the family.
I'm hoping her current sporadic activity is due to her working on upcoming workouts? Planning some fanstasitc stuff for the previously-announced 4-day split and step workouts. (I don't want to start a rumor, so don't anybody take it as gospel, but C. does seem to be 'absent' more often when she's got something cooking!)