That is an excellent question! lol
I had thought about this some, but not as much as I needed to. In theory the armies could have some sort of trained beasts, dragons or the like. But that wouldn't be fully practical.

The other option would be to leave the road in tact, but perhaps degraded. See when we played this world before, it was actually in the time period long after the wars, the road was broken and the people of each kingdom were completely forbidden by law from leaving their home island. But we decided it would be fun if we stepped back to the beginning of the first war, and the very beginning of the law not to travel. Just for more, drama in the story I guess. I always liked the fact that the road was broken, but it would make more sense for that to happen during the war, and some sabotage or something. 

Third option, would be a really good excuse to bring your airship idea into the mix. The road could be broken...or on of the kingdoms could sabotage the road, to give them advantage. Having read the plotline now, do you think the airships would fit in, without making things too advanced? I do like the idea of adding a hint of steampunk feel, without going overboard with it. 

Thanks for bringing up that question though. This is why I need help getting this together. I need smart people to help me work out the details :P

Another point of discussion, is whether we want to include elf & dwarf races. I talked with negative a little about this, and we don't think they would really fit in this world, but if for the sake of diversity everyone wants to add the races, it is definitely *possible* to fit them in this world.