I was going to say areas like North Haven or north of Semaphore & Exeter could probably be not too bad. The area nearer to Victoria road might be worth a look because there's nothing much on the river side, so it might be reasonably dark. Bit close to magpies territory tho...
I thing south of the Port River / West Lakes area is probably a bit to populated these days.
When I was a kid we lived in Renown Park. We used to camp out in the back yard & I remember it was pitch black and you could see stuff like the SMC, LMC, M42, & the milky way as clear as anything. Not these days.
Good luck with it.