If your tour was roads and off-road/wilderness...
What would be your tire selection? I am most interested in size/width, but if you have a specific model/tread in mind that would be good to hear also.
The way I see it is the wider the tire, within reason, the better it is off-road. In general terms, on-road is the opposite - smaller is better.
I ride 38mm 700c tires now on roads - and they are OK. Before, I ran 42mm's for a couple years and prefer that size for the kind of riding I do (and am going back to them).
By off-road I envision a mix of dirt and rock, forest roads, and some mud when its wet.
Is a tire in the 2" width range sufficient? Can pressure be regulated to accommodate for the difference in surface well enough?
This is just theory for now to wrap my mind around the subject. I have wanted to build up a Surly ECR - with the thought of multiple wheel sets for all-year-round riding. I didn't really consider the scenario of needing to multi-purpose one wheel/tire set before, though, so that is the reason for the question.