I booked in shihoainternational hotel in Miyun , Beijing. In April 2014

I see. You must refer to Shi Hao International Hotel in this county.

To Forbidden City, you can walk to Xinzhong Street bus stop to take bus no. 987 to Zuojiazhuang Station, where transfer to bus no. 120 to get off at Tiananmen East. Then you can easily walk there. It takes two more hours.

To Summer Palace, at MY Gulou stop, take bus no. 980 to Sunhe Station and then transfer to bus no. 696 to get off at Beigongmen Station, which is within walking distance from the north gate of the garden.

To Badaling Great Wall, it is 100km or further from the hotel. Yoy may consider renting a car or taking a taxi to get there, because it will be a little complicated to go by bus.

To Ming Tombs, it will also be best to rent a car to go. By bus, you can walk from the hotel to MY Huanbaoju Station to take bus no. Jiao 80 to Changping Dongguan, where transfer to bus no. Chang 67 to get off at Dingling. Then go for a visit.

Generally, it will be much more convenient to travel from Beijing city to these attractions, so if possible, I suggest you book another hotel in Beijing city.