If there is 7 of you, I would suggest hiring a 9 seat mini-bus and driver. If you can haggle in Chinese, there are loads of husband and wife driver guides and you can negotiate price. However, the guide will be a Chinese speaker.
If you organise through a travel agent they can do it all for you, especially if you need an English speaking guide. Try several agents, but I think the margins are pretty tight as competition is high outside main holiday seasons. I would not do any research now, as you will get the now price (Spring Festival). I would wait until a week or two after the hols. However, almost anything in China can be organised on the spot, as you probably well know.
However, there is a risk that if you buy a package they will drag you around all the markets to earn some commission from market owners. And so don't get sucked into a package deal. And avoid the cheapest deal, as they will have to make up the money somehow.
Seeing as you are travelling so far, it is unlikely that you will find a guide who knows all the sites. As such the most effective would be to find a guide in each location you go to, if you want in-depth interpretation. Or look at wiki-travel, lonely planet, etc before you go, and print stuff off.
We tend not to use tour guides. If they are from the site, they will often whisk you through quickly to get the next customer. Unless it is a very quiet day and she is a nice girl. My wife then acts as interpreter.
A good guide we will tip. This then makes it easier for the next family who not just focussed on price.
If the guide is not from the site, they will not know much more than you can find in half an hour on the Web.
I am not an expert, but that is how we have handled things when we travel. We hire a bus and driver, and look at a book for travel info. Only at some sites do we hire a guide.