Thanks, @tomcarpenter, glad you are interested in the subject.
About medical protection, it depends on your home base country. In my case, I am a french citizen and declare my revenues in France as a freelancer, so I am covered there and got a long-term travel insurance.
If you can manage your business with a phone, wifi connection and a computer, it is totally possible to do it on the road. You just have to considerate the time zone to be able to reach your clients on time. Wifi was really good in most of the countries I visited, and if you need a quiet/working environment, you can find co-working place easily where they can provide you private desk, print, high-speed wifi... and other digital nomads to meet.
I hope I answered your questions. Feel free to contact us if you have more questions :)
Thanks @digital-nomads Interesting information. Yes I have medical insurance from when I was an expat, though it is very costly to maintain. I would need to make the minimum UK salary just to pay the health insurance premium. Travel insurance is an option, though that can be very costly for the "older person". Particularly if your travel plans include USA.
Totally true, I don't know why they raise the price for USA and Canada, the risk to be sick there is lower than in Asia.