Elaine:
I am ethnically Chinese and went to China about 8 yrs ago - we did HK, Toishan ( rural village where my parents lived), Guangzhou, and Beijing. While lots of folks love HK - I just found it to be a big city with not any old ancient Chinese sights to see. We were there for 5 nights and that was more than enough and don't know that I would ever want to return. I loved Beijing and all the sites mentioned by others.
I don't know that you really need a personal tour guide in Beijing - which can be very expensive esp. when booking in Western type hotels. It was really easy to catch a taxi everywhere we needed with the hotel just writing down for us where we wanted to go in Chinese - in order to show to taxi drivers. At least 8 yrs ago -taxis were very cheap - only about $2 US for a ride anywhere within Beijing proper. The Forbidden City was my favorite and they had a great audio guide that was excellent - told you everything and more than you ever needed to know. And the English in the Audio guide was excellent - first class. Cannot imagine that a private tour guide would have done any better - esp. if you get one whose English may not be great. However, we did have some audio guides at the other locations that were not very good quality - with poor English that was difficult to understand. The only organized tour we took was one to the Great Wall and Ming Tombs - which is quite a distance from Beijing - it was fine.
Don't know what the situation is currently - but 8 yrs ago, the tour prices were exorbitant if you booked at the Western Hotels or online from the US. After a lot of online searching, I found someone that had been to China a lot, I was able to get the name of a local Chinese travel agent in Guangzhou. The prices for the same travel and tour services were SO CHEAP that I did book a private tour in Guangzhou for the entire day for our family of 4 and private transfers to and from airports. His prices for intra-china airfares were also about half-price for the same flights than booking from the US. I even tried US chinatown and HK travel agents - which quoted the same exorbitant prices. So at least in those days, the prices were about half or even cheaper if you book directly with a Mainland China travel agent.
For example, the Great Wall/Ming Tombs bus tour in those days was about $60 or $70 per person and I got the exact same tour for about half price. I even used the tour operator at the Marriott Courtyard Hotel, where we stayed, to make final arrangements for the tour and she was not happy that I had an email documenting that I had booked at about half price - but begrudgingly honored the price. Others at the hotel went on the same tour - so it is all the same tour operator with just agents booking in their behalf.
Of course, you are on business, so may not want to go to the trouble to save $$$ - but we were family of 4 at the time and I was an at-home Mom at the time - so really pinching pennies in those days.
The flight over to China is indeed a challenge - makes the 8 hr flight to Hawaii a piece of cake. It is better to go at night if possible, so you are tired and can better sleep part of the way when your body is tired. We flew into Chicago and had a daytime flight nonstop from there to HK - it was difficult. I cannot remember if they even had a designated sleep time - I just remember hating it. I have recently flown to Australia and Korea and it is better to have a designated sleep time to break up the trip. Even if you can only catnap - the whole plane is "sleeping" - thus, helps to break the trip up. They wake you up in enough time to serve a breakfast and you are there. So go first class if you can - definitely worth it. I have always gone cattle class and am still alive to talk about it!
Joyce