With bathrooms, Code now gives you two forks in the road.
- One 20A circuit can power only bathroom receptacles in any number of bathrooms, but absolutely nothing other than bathroom receptacles. Hardwired loads in the bathrooms (lighting, fan) must be powered by other household circuits.
- One 20A circuit must power one bathroom only, but can power receptacles and hardwired loads in that same bathroom only. This circuit cannot power anything in any other room. However, hardwired loads in that bathroom could be powered by other household circuits.
Rewire time is a great time to address problems like, as Jim Stewart says, breakers tripping when Mom and daughter try to run hair dryers at once. Honestly, I wouldn't even consider it excessive to supply two 20A receptacle circuits, so the occupant of that bathroom can run a curler and hair dryer at once. This could even be done with a single 12/3 cable using our old friend the MWBC.
As far as extending the bedroom circuit outside, that is fine. However I learned not to leave expensive electronic things outdoors. That includes GFCIs. I would fit a cheaper indoor-rated GFCI+receptacle inside the bedroom at whichever location you tap for the outside extension. Hang the cable to the outdoor receptacle off the
LOAD terminals of that GFCI. Then, fit a plain receptacle outdoors. It won't deteriorate nearly as fast, and when it does, it's $2.