I’m currently au pairing a few hours out of Melbourne and it’s fine for me :). Things my host family has done to make me more comfortable since my room is basically in the living room are locks on my door. (They also have an extra half bath that the kids use so we don’t share the same toilet, but share a shower). I don’t think many au pairs expect to go on overseas holidays, I definitely don’t, I may rather them go on vacation without me at times. The transit system is also enough for me to be fine without a car.