Easy. Belmont is very well located for you to live somewhere dark.
Head east. DO NOT head north or south along the coast like the rest of the beach addicted population
Head east and you can get a house in suburban or semi-rural hills areas (Kalamunda - outer eastern parts, Bickley, Carmel, Pickering Brook, Parkerville, Stoneville, Mundaring, Gidgegannup, Chidlow, etc). All of those will be about a 30 minute drive from Belmont in normal medium traffic congestion.
I live 35km from my work near the CBD, takes me 45min in peak hour each way, drive through Belmont every day on my way to/from the hills. I walk out side at night and can easily see the Milky Way and LMC, SMC takes a little more adaption, and I have a streetlight 20m from my house!
Completely different story if you live "on the flats" as opposed to in the hills.
When/if you're seriously looking, I'd be happy to give more detailed information. There are better and worse areas for possible future light pollution of course.
Oh, and if you want really dark, you do need to travel, because it's all so flat the light pollution dissipates gradually. I travel to a spot about 1 hr 45 from my home in the hills and you cannot see any light pollution there, but it is about a 2 hour drive as I said, closer and you'll see the glow of Perth.