Qifeng Park is Dongguan's most useful urban escape, a wooded hill park east of the centre with paths climbing to viewpoints and the Huangqi Guanyin temple area. It is not wild country, but it gives you space, trees, and a look back across the city.
Go early or near sunset, when the heat is softer and local walkers are out on the paths. It works well after Keyuan Garden if you want a day that mixes old city culture with a little exercise.