IMHO, I'd say "yes", beings that you are also changing the clutch/brake fluid.
I don't think it is terribly difficult to change the xmsn fluid. I've changed it twice in a Ranger I once owned. It's a bit messy, if you don't have the right tools.
If you are going to travel that far and that long, it would give you greater peace of mind if you did. There is no better feeling than taking a long road trip knowing that your machine is in top shape, I think.:thumbup: