I havent been there for about 9 yrs. It was busy then - must be worse now. Do you stick to Moreton Bay ? Its not far to either the GC, Yamba or Wide Bay
Apart from long weekends, I am usually limited to day trips, where ever I can get to and back from Victoria Point in 4-5 hours (about the wife's limit, she's new at this and finds it stressful but is getting better)
Long weekends (Australia Day and New Years, so far) we did over nighters, biggest problem here is the small cabin on the tri is tight for 4, even though the kids are still youngish. I will need a bigger cabin (boat) before we could go further than an overnight trip.
Yamba or Wide Bay, That's an outside trip, wife and kids not ready for that yet, don't want to push the issue to hard, they are still scared that boat will sink and they'll all drown, though they are over coming that fear, I'm not going to consider an off shore trip till they're emotionally ready.
GC, well we spent new years eve at slipping sands, thats getting down towards gold coast. That was our first overnight stay and much more comfortable than One Mile. Only problem was finding some sand banks which made me glad I chose a Tri.