Well, first of all you should move all your summoners to the securest lab closest to the front. What is the sense in summoning some units only to make them walk all the way there? With summoning, your mage is like a factory and if your factory can walk then it should
You should definitely move the bulk of your slow troops with magic. Moving additional commanders to the front can be done with Flying Boots. Just forge some up and hand them out to new commanders as they leave for the front. Then drop them off at the closest lab to the front for the next commander.