Hello and welcome to the forum,

The most straightforward answer to your question is that you will require insurance for the car in every country you pass through and there is no requirement for medical insurance in any of them but you would be wise to get some in case of some medical emergency and you will have to get this in your home country in the form of travel insurance that covers you abroad. You can possibly get vehicle insurance that covers you for the UK and Europe on one policy but after that you will need to get local insurance at each border, there is often a seller just after customs and immigration.

Things change and possible routes come and go depending on the political situation in each country and how your own government is getting on with the one you plan to pass through. As things stand US passport holders cannot easily travel through Iran if at all ruling out the India route unless you ship around and Burma is closed with no sign of reopening anytime soon.

It is possible at the moment to drive through Turkey, Georgia, through a small part of Russia to Kazakhstan, a US passport holder on here or Advrider travelled that route last summer but obviously things can change.

This route also does not require a carnet de passage unlike going through India, I presume you have already looked into importing your car into China? If not this is the first thing to do before planning anything else.

This is not a motorcycle only forum, car drivers are welcome and is arguably the best place for the information you are after.