A trip I'm looking to put together sometime in the next two years is a big extreme.. I want to ride my bike home (to California, unless Europe distracts me).. from Korea. It's been done, and it's my kind of lovely: camping, physical exertion, exotic foods, and lots of time by myself. Probably also photography and journaling.
I really have no idea how I'd do this, since even on shorter biking trips, processed foods tend to be a regular feature.
Ideally I'd love to cook for myself, though depending on the gear you need to cook things, you have to weigh the costs of the extra weight on the bike, and while weight itself isn't necessarily a deal breaker (touring bikes can handles quite a load), space is often at a premium and you can't exactly take a hand blender.
I imagine I'd try to keep it simple, and buy basic and pre-cooked ingredients along the way, and make the most of street food when in more populated areas. I do imagine I would have a basic mess kit and a camping stove, I consider the ability to create fire an essential, as much as being able to source clean water no matter the locale.
For sake of flexibility though, if you get an invitation to dinner or to camp in someone's yard, one tends to be hungry rather than picky when it comes to food and your body becomes an absolute furnace in terms of burning through food at times like this. Still, I wonder how complaint I would be able to stay, and certainly there are vast stretches of Central Asia that have excellent vegetarian and meat based cuisines.
So far, for me, avoiding soy has been the hardest. (I'm kinda in one of the soy Meccas here in Seoul.)
But it's something to ponder, and something to try out on shorter trips first. I would love to hear about others who've gone the road less traveled with their Whole30/9 philosophy and were able to stick it through.