Can I travel in China by myself if I get visa?

I want to travel in China. Iam an American citizen.WhnI get my visa, that's mean:Can I travel by myself? I mean buy a train ticket at Beijing Railway Station and go to any province. Take a tour in Beijing at my hotel reception?

When I get my visa there is any regulatio to travel to Lahsa? Any especial permitton. I'd like to konw any information abou my questons. Thanks a lot in advance for your help.

MR. FRANK AVILA