In reply to toad: The timetable aren't (and have never been) user friendly.
These days there's only one direct bus from Bangor to Ogwen Cottage, however you won't see it on the standard bus website because it runs from Llandudno to Llangollen (the X6) and therefore is a Conwy bus so it isn't on the Gwynedd or Sherpa website.
The timetables are also filled with incomprehensible codes about holidays, school days, weekends, alternate weeks etc etc.
Last time I complained about the timetables not being updated on the ground I had a long rant about sustainability and the Green Key, and had a useless reply from someone with an extremely unhelpful bad attitude.
My current solution is to save up and buy a car. As much as it pains me to say, I don't give a crap about attempting to use green travel in Snowdonia any more, and I really don't blame anyone else for wanting to drive into the park.
Toad - are you talking about P&R in the Pass at Nant Peris? Because if so (these days) the buses do enter the car park.