very neat, 4 inchers, wow. can see how they would be great for being on roads like and especially worse than the one in that shot of you. From the comfort side of things and the "float" aspect of them, for soft and/or wet stuff. What sort of psi do you run, lets say like in that photo--ie, load, road surface? 40 psi is my first guess?
As for the simplicity angle of not having a fd, I guess horses for courses. In rough stuff, mucky and all, I can definatley understand. As I understand, the IGHs are very well made and therefore gets rid of the maintenance issues of a rd also.
For the road touring Ive done, regular old fd and rd arent an issue, keep everything clean and lubed, they generally work.
With your terrain, the possibility of a fall and dings are going to be so much more possible, and damages with it, so I can see going simple.
But not for road touring, give me more gears and especially low ones and I am happy (me and my knees)
Oh, I can see however not wanting a front derailleur etc, as your spare tubes and fist size patches must weigh about 10 lbs so you have to take some lard off elsewhere ;-)
In that pic my front tire was 9psi and my rear 12psi. I'm not suggesting front derailleurs don't work or rear derailleurs for that matter. I just enjoy simple clean chain lines and I'm not finding 8spds for example any handicap at all. When I have to replace the drivetain on my LHT it will get an 8 or 9 spd setup. I'm not worried about how much it weighs now.