Backs onto conservation, connects to the walking trail, and gives you over 3,700 square feet of finished living space. Welcome to 17 Mason Drive in Alliston, a 4 bedroom, 5 bathroom home in the Treetops master-planned community, set on a premium lot with no sidewalk in front. The curb appeal is clean and classic, with a brick exterior, stone accents, covered entry, and double car garage. Inside, the home opens with a bright foyer, high ceilings, large windows, polished tile, rich hardwood, and a carpet-free layout. The main floor has the spaces people ask for most: a dedicated office, formal dining room, living room with fireplace, and a well-planned kitchen with quartz countertops, stainless steel appliances, upgraded cabinetry, servery, centre island, and breakfast bar. Upstairs, all four bedrooms connect to an ensuite or semi-ensuite bathroom, giving each room better privacy and function. The primary suite adds generous space, dual walk-in closets, and a private ensuite, while second-floor laundry keeps daily routines simple. The finished look-out basement feels like part of the home, not an afterthought. South-facing natural light fills the space, making it ideal for movie nights, workouts, guests, play space, or a second living area. A large storage area gives you useful space now, with potential to finish more later. Out back, the setting makes the home feel different. You get stone patio space, garden beds, room to sit and unwind, and conservation and trail access directly behind you. Treetops offers approximately 7 km of walking trails, parks, and playgrounds, with Nottawasaga Resort nearby for golf and vacation-style amenities. Highway 400 is about 10 minutes away, with easy access to Barrie and Vaughan.