Actually I think most of the plans presented are too complex
The "troops" you have to work with are not going to be any better quality and maybe even worse then the colonial militia during the American Revolution. Our population is composed of a lot of well meaning people who have never really faced any physical hardship in their lives. Outside of a few Special Operations types we've seen no real heavy Infantry combat since Vietnam. The last time we ever were in a position where we could lose on the battlefield on a large scale was Korea in the early '50s. Most Korean war vets are in their late 60s or older by now. The Vietnam generation is aging. Add in the incredible tooth to tail ratio of American forces and you'll be lucky to find 10% of your vets who served in ground combat arms (Infantry, Armor, Artillery, Engineers) . Most of the rest will have had exposure to military discipline, but will have almost none of the skills you need to fight with.
Among these you will have those who would try to prosper from the situation (it happens everywhere, it's just human nature), and many who will want to use the situation to further their own agenda. One thing you haven't taken into consideration is those fringe groups who will use the Moronian invasion to seize a little power for themselves. Colonel Edmund may very well have to fight Imperial Grand Dragon Donnie for control of the forces. Imperial Grand Dragon Donnie may have several followers who have stockpiles of military stores that may be usefull to the cause. Some of the sheeple will naturally side with Imperial grand Dragon Donnie because they will feel safer, because with his camo clad followers he may appear the more competent and prepared leader. Grand Dragon Donnie may even want to negotiate a seperate peace with the Moronians if he thinks it will benefit his cause. Others will be reluctant to leave their homes and families to the protection of others. Some will want to head out on their own to engage the enemy. About a third of the people will want to do nothing and stand by and watch as the Moronians march by.
You have less then 12 hours to build a fighting force out of this mix. Simple tactics where all your soldiers can see one another will be the order of the day. You will probably have some small hastily thrown together units that can scout and perform other functions, but you will still need to lead this group from the front. Sam, with all due respect, if you had six months to train, you might be able to pull off complicated operations that Colonel Edmund could direct from his TOC. In 12 hours, you will be lucky to organise much of a defense. The best you can hope for is to hold them long enough for the Army to get there. The only way is to use the natural obstacle you have, the river.
12 hours would barely be enough time for a trained brigade with a lot of engineer support to organize a defense in depth. Blow a span of the bridge, get your forces online on your side of the river and hold. You will have to commit a fairly large force to internal security in the town to keep order and prevent looting. You may have to disarm and lock Grand Dragon Donnie up or even kill him in order to stay in control.
Unfortunately this won't be the romantic story of people coming together to save their homeland. It's going to rip families apart, destroy lifelong friendships, and cause terrible loss of life if you decide to take the fight to the Moronians right away.
Lets look at the history here, in occupied Europe in WWII various resistance units not only fought the Germans, but they fought each other, when there were no Germans around to fight. What makes anyone think things would be any different here?
Jeff
I would like to have and keep the iniative, especially since I concur that our fighting force is not likely to hold under sustained fire. With that in mind, I am not overly concerned with ammo supply.
Perhaps the Moronians (obviously backed by the CHICOMs) came into the country in containers on Cosco freighters.