I'm pregnant with #2 in DB. I had #1 whilst I was living in DB as well.
I caught the bus/ferry/taxi to Matilda, no problems. In the ante natal classes the midwife told us that we'd just KNOW when to go to hospital. Sounded like a load of garbage at the time, but she was right ! I caught the 4am'ish ferry (small one, v.uncomfortable whilst in labour, not recommended). Arrived at Matilda around 5.30am. Baby arrived at 10.30am. I was very happy with the experience. Contractions seemed to slow down whilst I was travelling, maybe because I was concentrating on getting there.
With #2, I intend to leave earlier, as I understand 2nd babies come faster.
A friend of mine recently had her baby whilst living in DB. She had planned to go to QMH. However, she woke at midnight with the first contraction, couldn't make the 12.20 ferry, next one at 1.20am (not sure I have the exact times right here, but they were an hour apart). By 12.30am she knew she wasn't going to make the next ferry and called an ambulance. Ambulance arrived within 5 minutes. She delivered at Princess Margaret at 2am.
Hope that helps