You know that road from sanjiang to runan? every time we have an offensive theres always another offensive army trying to take our land to then we have a large battle trying to break threw each others army. well that just waste to much time trying to take out that offensive army stopping our progress to runan. we should still attack that way but have at least two ships with tons of people in them and land in runan harbor without being detected then attack the offensive army from the back, meaning that we are attack them from both sides quickly destroying them and having a easier time to runan.
So basically have 2 teams the first team will attack from sanjiang to runan while team 2 get in the ships and sail towards runan harbor and when team 2 lands in runan harbor they will help team 1 by attacking the enemy from the back causeing confusion and that should quickly take out the enemy and when the enemy is gone both teams will combine as one and head to runan.
Or if anything goes wrong with useing ships then we can go threw the mountains that leads to runan and the do the same thing but not with ships.