The area around Keynsham is properly green, and the figures are underselling it if anything. The average home sits within roughly 150 metres of a patch of green space. There are more than twenty of them inside a kilometre. Open water is about 400 metres away, courtesy of the two rivers that meet here. Countryside starts more or less where the houses give up, and it does not stop again for a while.
That density of green is the town's best card, and it plays out on the ground rather than just on a map. Memorial Park runs along the River Chew through the middle of the place, the sort of park with a bandstand and playing fields that a town either has or quietly wishes it did. On the edges it turns wilder. The Manor Road Community Woodland was planted across former green belt between here and Saltford, and Keynsham Humpy Tumps is a scrap of unusually rich grassland hanging onto a slope beside the railway line. The Avon Valley Country Park sits within reach for anyone who likes their nature with a ticket booth. None of this is designated as a National Landscape or a protected scientific site, which in practice means it is green you can walk on rather than green you admire through a fence.
The setting is village and river valley more than suburb. Keynsham sits where the River Chew joins the River Avon, with Keynsham Lock and its island pub marking the water's edge, and the country around it is stitched together with small places: Saltford next door, Chewton Keynsham down by the river, then Compton Dando, Publow and Queen Charlton further out, each a proper village rather than an estate with ideas above its station. The larger pull is the shape of the whole thing, a town dropped into a river valley in the corridor between two cities, near enough to both that the fields never tip over into isolation. You get the green without surrendering the shops.
The area around Keynsham is about as good as this question gets. Rivers, parks, woodland and a ring of genuine villages, all within a walk or a short drive, and a top-mark rating the ground actually earns. If the surroundings are the reason you are buying, this is the strong end of the market.