Having lived in a few places across the hills, I'd say give Roleystone a look in. It's generally cheaper than Lesmurdie/Kalamunda to get established on a big block and more socially and legally acceptable to dabble in hobby farming if you want. We and all the neighbours keep livestock and nobody gives a damn. It's also got a weird microclimate that makes it great for growing all sorts of produce you generally only see further south. Orchard country. Much more of a community vibe to it too than L/K. Almost like a country town.
I'd also rate it better than Kalamunda/Lesmurdie in terms of amenity. The big drawback to hills life is how far away you are from the rest of the city, public transport, the big shopping centres etc. Roleystone doesn't have as big a shopping complex as Kalamunda does, got a good IGA, a fucking fantastic bakery and a mom and pop hardware store. Plus, it's only ten to fifteen minutes away from the Armadale shopping complex and 15-20 from Carousel, which is just as long or shorter than it'd take to get there from Kalamunda. It's only five to ten minutes to get to Kelmscott train station, which is itself half an hour from Perth.
Fire is real danger. You're more likely to get snakes, spiders and all sorts of annoying insect invaders. Nobody will want to visit you unless they're staying the night, especially if they're from the shudder northern suburbs. Larger blocks can be a right pain in the arse to manage and keep from getting overgrown, so be wary of biting off more than you can chew. Storms are usually worse in winter and power outages are more frequent. Summers are generally a touch cooler, but we don't get the Freo Doctor so it kind of evens out You'll usually get mains water, but be on septics or blackwater recycling for sewerage, and you'll have to go pure electric or bottled gas for heating and cooking (and then you will invariably forget to order a new bottle at least once a year and have cold showers. Go pure electric).
It's got its challenges, but I know my neighbours, the shop clerks know me by name, I keep chickens and other things, I grow fruit and veggies, it takes me less than an hour to get to work, and everyone who visit marvels at the view. Wouldn't trade it.