My Opinion If Korean War 2 were to breakout.

US personnel would be in danger Military and Civilian.

Camp Humphreys, Casey and Hovey if its open still will be "The Alamo". Anything that would be air would be obliterated. US military thinks that K16 and Osan air force base would survive. In my opinion it would not survive. 10% to 30% of personnel would escape Camp Casey/Hovey. About 40% would escape the mess that would happen at Camp Humphreys just a guess of course. Military would have there orders. However, the civilians will have a choice although I feel its one choice and its to assist the military on there endeavors and here's why. US Military underestimates DPRKs tow artillery and other defense mechanisms that would make the peninsula unflyable for about 4 or 5 months until the US regains control of the airspace. From fleets from carriers, Japan and Hawaii. 

A US civilian on the Korean peninsula can be a bargaining chip for the South Koreans. All it takes is a threat from the DPRK military for the South Korean Civilians to give up the whereabouts or surrender US civilians tot DPRK forces this would be a problem because Koreans are going to protect their family and friends they remember what the the Americans have done to them recently which is disrespect them because of cocky commissioned officers treating them like complete garbage. This would be prevalent in urban areas where bunkers are mere subway stations and South Korean civilians have a disposition against US civilians. The only place they would not be given up is in the farm lands. Farmers are more inclined to protect the US civilians because they remember the 1st Korean War however this is not a guarantee for the US civilian. The US civilian would also endure any hardship being in a safe place with the South Korean Farmers.

A US civilian is more inclined to follow the US military. US military's mission is not to protect US civilians in most cases. So what the US civilian would have to do is provide or offer a service as well as being able to assist the US military in their operations. In otherwards they are conscripted into the US military. No matter if they are Business Division Chief for MWR functions or a dependent mopping up Post Exchange Markets.

These US civilians who choose to move with the US military have the right to pick up weapons off of deceased military members of either the US, ROK, JAPAN or DPRK military members to defend themselves that is their right! This is why in these situations arise in a position like this a civilian commander needs to be set so they can act and advocate for the US civilians.

US Civilians would most likely pick up DPRK weapons to prevent any pushback from civilians taking weapons from Japanese, US Forces  or ROK army casualties on the account of supply of the regular army of the 3.

US military would conscript anyone 18 or over for military service since the beginning of the war would be bloody and brutal. Most conscripted civilians would carry DPRK weapons. Or if the armory calls for it the civilians will carry anything that is an upgrade from the DPRK weapon.

US civilian commander has the authority to disband the civilian unit from the command of the Korean US armed forces for the following infractions:

(note. Any civilians that are against the order can remain with the US military command or is able to disperse into another function.

The US military is conducting Illegal operations

The US military is conducting genocide

The US military is in a My lai massacre setting and the Civilian commander authorizes disbanding to the nearest US military base wherever that might be. 

US civlian will have the right to disband from the Civilian Commanders unit if the Civilian commander sides with the illegal operation of the US Military Commander.

Breakoff Unit will assume command of the unit either by an elected leader, or by no command with the mission of getting to Chinhae naval base or a surrendering to a Japanese military command or ROK army military command.

My guesstimate will be this. More than 50% on this peninsula will be meeting Jesus. Honest opinion here is the US will make the mistake in informing anyone whose a US citizen to enter the bunkers, which are the subway systems. Those citizens will get slaughtered along with South Koreans. DPRK military will follow the rules of war for the most part but they will not hesitate to end Americans.

Any transport planes will be shot down to create chaos. US civilians will play a part in this this war that never should of happened. US government will never acknowledge. Korean Peninsula will become either a Civilian dictatorship or a military one.

Here is what I'd imagine my day would go if 2nd Korean War were to happen. An MWR director would remember me as someone's son or something IDK at this point, calls me up for me to become the MWR business manager of the Gateway Club formerly Primos, formerly the Impact Zone etc. I become that manager. try to bring it back to its glory install a boxing ring into the club along with the old functions it had. I would then try and reestablish it as a Monte Carlo with table games which made MWR money till a Regional Commander took it away. I would think id bring the club back to solvent but before that the 2nd Korean War would happen. I would advise my staff to go with the 2nd Infantry or 1st Tank which I'm hearing is still there, I would advise everyone not to take any planes (peninsula will be shut down for a couple of months since K16 and and Osan would be obliterated). I'd evacuate everyone but myself, I would destroy or protect anything that the enemy could use and would go with any outfit of the US military to get out of the area. I'd follow any US military outfit to save myself even if I had to be conscripted by them so be it.