Hainan sure seems like the way to go since the Chinese are, in effect, "designing" this place as a tourist destination
with a more yacht friendly environment
However, I am not so sure that one can discover "Chinese culture" there. Hainan is a unique environment
, as I am sure you know. Plus, as seems to be true of EVERY Chinese port of call that I have investigated, certain restrictions will apply.
Certainly, if you are a Taiwanese resident and/or foreign national (ahem) there would be restrictions on where you could visit once hitting Hainan, which is, of course, an island. Would the Chinese officials permit
you to go "inland"? Perhaps, that would be possible, depending on the the type of visa that you might be able to aquire in advance; but, from my understanding, your boat would not be able to accompany you "upcountry", and you would have to leave it on Hainan, in trusted hands, most likely at significant expense or with family
, while you explored the mainland.
As a caveat, I have to admit that most of the last paragraph is mere speculation based on my internet research
and my correspondence with folks like you, who, like I, have been interested in touching down on the China coast.
Please consider the above in the appropriate context, and best of luck with all your boating