Will I be okay travelling in and around China with only basic Mandarin?

and english of course, oh and okay Japanese but i dont expect that would come in very useful.

I want to go to Beijing, Shanghai, Taipei (Taiwan) and Hong Kong.
I know in Hong Kong they speak mostly Cantonese so will I have trouble there?
and are there any other places that dont speak much mandarin in case I decide to add somewhere else to my list?

I have travelled to China and Hong Kong on business often. English is spoken everywhere in HK.
Ouside the main business/tourist areas of China there is very little English, so if you only have basic Mandarin you could have problems.

I think that you will be fine - I live in China and get by with only a few words.

You will find in the big cities that you are visiting, a lot of people speak English and the Chinese are more than happy to help a foreigner.

The best thing to do is to get a pocket dictionary and point to what you want on there - The pronunciation of some words can be difficult. Also look on some websites for survival Chinese, print off these phrases and point to them.

Good luck, China is a great and friendly country - you will have a fantastic time!

Yes, its okay. No, as many Hong Konger speaks English, its no problem at all. I frequently visit Hong Kong and I comminicate with them in English, so its not a big problem at all. Most people in China speaks Mandarin so its not a major problem for you, unless u visit rural areas or minority tribe areas.

Careful if they notice you arent strong in Mandarin they will try and rip you off. However you should be fine with basic Mandarin, the people in Beijing speak a really difficult lingual/accent of Mandarin thus you might have trouble understanding. You should also know how to read Chinese as the signs and stuff barely have English. In Hong Kong you should definitely have no problem as many people there know English and signs and stuff also have English translation.

Another place you should go is Macau and Guangzhou. Macau is similar to Hong Kong. Whereas in Guangzhou people speak both cantonese and easy to understand mandarin.

A train from Hong Kong will get you to Guangzhou and a ferry will get you to Macau. From Macau you can catch a bus to Guangzhou.