Hello Lauren & fellow ziners,
Your son and his friend are going to love their trip to China.
It's easy to travel within the country (language is the only barrier but can be overcome), there are wonderful sights to see and the people are very welcoming.
As for safety, there are pickpockets but violent crime is rare. For instance, in my home town of Beijing an assault especially on a Westerner, is talked about for weeks versus my former home town of New Orleans where it is a daily occurence.
Wilma mentioned Suzhou, Hangzhou and Guilin which are excellent places to visit and there are so many more. Beijing might be a good city to start, your son will find many foreigners his age for a support group while he is here. If he plans to stay in youth hostels, there are many around the city. He can take the train from Beijing to Xian and on the way stop at the ancient walled city of Pingyao for an overnight. They can then head south to the cities mentioned above.
Sidenote on ATM's in China: They are quite widespread now and it's the easiest way to get cash. The most cost effective way is to use a credit card's emergency cash option. For instance, American
Express will allow a cardholder to get $1,000 USD (or equivilent local currentcy) every 3 weeks ($2,500 USD for the gold card). The official exchange rate of 8.28 RMB per USD is used. ATM's rate is about 8.17 and the worst rate is the credit card of about 8.10 (or less). I would not bring Traveler's Checks to China, they are very inconvenient.
Lauren, if you want to email me separately, I will be glad to give your our phone numbers to help your son when he visits.
Bob and Jeanie Beijing