I would definitely get a tent, to keep off insects such as mosquitos, and dust too, or any other elements such as wind, snow, rain. You may want to get a trailer to carry your gear, so choose a good strong overland bike. Make sure you know how to do your own repairs.
Some times it is frustrating to get through some countries, most of which have some bureaucracies which do everything with lots of red tape or paperwork, if not also bribes.
If I were you, I would start training right round your community, taking at first short trips, say, from your place to another town or city, or about the countryside.
Learn to use maps, compass, and learn at least three other languages; by that I do not mean fluently, but enough to get around. I would choose French, Arabic, Russian, and/or Chinese. Or at least carry an interpreting device.
Be prepared for mishaps, or to put it another way, be advised that Murphy's Rule is not joke, at least not when it's happening to you. So a sense of humour, the ability to adapt, overcome, & improvise, is a must. Also, you might want to develop some contingency plans for certain situations, such as "What happens if I am robbed? What do I do if my passport gets stolen?"
Have you read about Danziger's walks from somewhere in Europe through Asia? Or of the fellow who dressed as a Bedouin and went to Mecca back in the days before the demise of the Ottoman Empire?
If you can get a network, such as some dependable friends or family, to help you, by all means accept their assistance in getting food and supplies mailed to you at pre-arranged drops or mail centres. Of course, this would be non-perishables and such.
You might do well do get sponsors. In order to get this accomplished, you will want to be able to show them that you have a proven track record of starting and finishing "expeditions" or "adventures."
Last but not least, make sure you have both a good physical (medical) and psychological exam. Last thing you want is to either come down with illness or lose your sanity while you are abroad.
I wish you the best of luck. Be well, good traveller!