I've been over there many times, always with a Chinese speaker but only once have we done a tour and we weren't happy with that--since then we've always done it on our own. (Note that while she speaks the language she does *NOT* know the areas we are traveling to.)

If I were to go alone I wouldn't be looking for a guide. The web will give you the information you need to decide where to go. Beyond that you need to have all the addresses you want to get to WRITTEN DOWN. Do not attempt to tell a taxi driver where you want to go, they're not going to understand you. Show them a card with the address and there shouldn't be a problem.

While the people in the tourist areas will speak little English they are at least used to dealing with foreigners who don't speak Chinese. Even when you get off the tourist track things usually work pretty well. When we are over there we normally mostly do our own cooking and I do at least 80% of the shopping--never have I seen any sign of a word of English being spoken there, the only time it's been an issue is when they moved what I was looking for.