There are some mountain travel route in the picturesque Xishan Hill (西山)and we used to call "XiangBaLa"(香八拉), meaning from the Xiangshan Hill (香山)travel to Badachu Park(八大处公园). Such lines have dozens, of different lengths, can adapt to all kinds of people.
This route is not difficulty from the Biyun temple(碧云寺) —YuHuangDing(玉皇顶)— XiaoSiKeShu(小四棵树) —YingTaoGou(樱桃沟)—WoFoSi(卧佛寺)—Beijing Botanical Garden(植物园) and total range is about 8KM so it doesn't make you feel tired.