I don't post up too much, but your pictures so far look like an epic ride. Just some input since you asked.
Personally, I would probably use GPS to do the ride.
Tarmac isn't too bad a thing if its gets you into interesting little towns and sights. One of the things I enjoy is meeting/taking to natives. For some reason, I've found most people very receptive to motorcyclists (esp when you're from far away). Just helps with "experiencing" the people and land. Keep in mind, some people will try to do the whole thing at once. After a few grueling days, road is not so bad. I'm not talking 600mi days here, but surely a 60-70mi interesting backroad stretch through quaint towns and historical sites would be welcomed at times. Also helps with gas stops.
I will end it with its YOUR route. Do what YOU want to do. I think its almost unthinkable, so stay focused. Just your will so far has me wanting to send you money to help with travel costs. While I can't help you with the route (see my location), I will say that by the time you're finished, I'll be due for a good soul cleansing, and this looks to be just the ticket!