I think doing a tour that size you would be better served with a touring bike. Cyclocross is a great sport, but what it requires from a bike is not what touring requires. Cyclocross bikes are built to be nimble and quick steering to get around obstacles, they have high bottom brackets for ground clearance, and generally pretty short chainstays. Touring bikes are designed to be steady and stable more than agile, with low bottom brackets for stability, and long chainstays that allow more room for panniers, and provides more comfort to the ride also. I think some shops get confused because a lot of cross bikes have mounts for racks (think commuting) and will take wider tires than a road bike. The cross bike might tow a trailer okay, but they do have a bit of a reputation of beating you up on long rides, as they weren't designed for comfort, but a 45 minute to 1 hour race in the dirt, mud, rocks, or sand. I wouldn't mind a cross bike, but it certainly wouldn't be to replace my Cannondale touring bike.