I was also wondering about what type of bike to use. I just finished a tour in New Zealand on my Surley LHT and was wondering how it would handle the Great Divide Trail. I am sure there are some rough areas but it seems the majority is dirt road. I rode about 100 kms of dirt road in NZ and it worked well. I think if I put on some large 29 inch moutain bike tires on it may work out.

I have a full suspension mtn bike, but it looks like I would not need such a bike on the route. Would a hardtail mountain bike be better? Are the trails technical enough in places that the geometry of a mountain bike would be better to use than the touring bike, such as steep rocky climbs and decents?

Anyway, thanks for any opinions that you may have.