Hindsight really is 20-20. You can ponder over all of the things that need to be done, think you have it all well in sight, then suddenly look back and say: “I wish I had ___ when I had the chance.” Read below and see if you considered the following:

1. Collect intelligence on the current situation
Before you start phase 1 of any operation, you’re essentially in phase 0. This means that you should be shaping your environment, to include setting up ways to know what’s going on (which is what’s called Intelligence). During an EMP that blasts across most of the country, the first thing you’ll notice will depend on what time of day it is.
Make sure you get in touch with your neighbors. This could be critical not for just figuring out what’s going on, but for neighborhood security and augmenting skills you don’t have.
At night, the first thing you’ll notice is all the lights just went out. If you’re driving, your car will most likely stall. I say “most likely” because we really don’t know what would happen in real life and the exact circumstances would vary widely depending on the type of EMP, its altitude, atmospheric conditions, and the type and placement of the electronics and any shielding. We just don’t know.
Let’s assume you’re home, and it’s just after dark. All you know at the moment is that you lost power. So how would you know that this is a widespread event and not just that a tree fell on a powerline?
First thing would be to pick up something that would be susceptible to an EMP but not tied into the power grid. Check your cell phone for power. Check any battery-operated device.
Some things probably won’t be affected by an EMP though even if it’s strong so you’ll have to use some logic here. A metal flashlight that contains just a bulb, batteries, and wire would probably survive with no problem. A plastic one that has a little micro-controller circuit in it would be much more likely to fry.
Now, since you set things up previously, you pull out something electronic that you’ve stored in a Faraday cage. If the cage was constructed properly, it should protect your electronics against a decently-hard hit. There’s a lot of real crap out there on the web about how to build these things though so do some thorough research.
So at this point, you should have an idea as to whether the things in your home work or not. Next thing would be to start your car. Not only will this give you another indication, it’s necessary information to know how you’re gonna react.
Next thing you need to know is how widespread the EMP is so you’ll have to communicate with someone not in your immediate area somehow. Unfortunately, communicating long-distance pretty much means you have to use electronics. Hopefully you stored a ham radio in some kind of shielding (and not had it still attached to the radio). Many ham operators do this and most repeater stations have emergency power backup. I personally have a Yaesu 857d, that works very well for things like this.
Also consider that an EMP would develop massive power along any power lines or phone lines, which would most likely cause fires in the affected area.
What, or who, you check into next will depend on your own circumstances, but at this point, you should have an idea what happened. Based on that assessment, you decide that it meets your criteria for leaving town.
2. Gather gear and personnel for movement
If you’re already at your primary rally point, such as if you’re bugging in, best thing to do is immediately fill your tubs, sinks, pots, and other containers with water because that pressure probably won’t hold for long. Then move to gather your stuff in case you have to leave. Your plan must on some level involve bugging out at some point.
This is where you grab your bug out bags. Hopefully you’re not like most preppers and have 70 pounds of gear, or even worse – don’t have your stuff together and end up deciding at the last moment what to put in your bags. My bug out bag is currently is only 25 pounds plus whatever water and food I’m gonna carry (except when I’m traveling on my Harley, in which case all that gear and more is on my bike. If it works, I’ll ride it as-is. If not, two of my bags are weather-proof backpack/duffel bags and I know where each and every item is on my bike so I could assemble my gear in a few minutes).
Before you can move out, you’ll have to find everyone else with whom you’ll be traveling, and they’ll have to have their gear together.
Most likely, you won’t have everyone at home when it hits, so the next thing to do is try to establish comms.
3. Move to the primary rally point
In most cases, your primary rally point will be someone’s home but not in all cases, and for all you know, that home may not be there once you get there. Everyone should have noticed something happened and remembered during training that when ‘X’ happens, they should move to the primary rally point somehow.
You should all have already planned your bug out routes to get to where you need to go, which makes it much easier. Shit happens though, so you can expect that once you get there, someone will be missing. Make sure you wargame that scenario for each missing person or group of people because your next steps will depend greatly on who’s there and who’s not, and may also depend on what you’ve all brought or failed to bring.
Also, consider that you may find out that your primary rally point isn’t useable. The neighborhood may be rioting, the forest could be on fire, a roving band of baboons may have been given human-like intelligence by a mad scientist and started a commune there – all sorts of things. You need to have a secondary and at least a tertiary rally point set up that hopefully wouldn’t be affected by the reasons you can’t use the primary.
You may also find that for whatever reason, you have to move to a new location that wasn’t planned. Try to leave some sort of message to later parties who arrive so that they notice it and understand the message. In certain scenarios, you won’t want anyone else to understand the message though.
One example could be to stack rocks in the shape of a ‘4’ and the arrow defined by the triangle inside the four points toward the point where the two likes overlap (bottom right as the 4 is read). You might also add something underneath one of the stones such as a note or even more discreet, a symbol (anything blue meant you headed toward water in that direction, for example).
4. Establish comms with your missing team members
Once you’re at the location you’ll be staying at for a while, you may find that not everyone is there yet with you. If you’ve already established a radio plan with everyone (and they have comms that were protected and still work), you’ll probably have a time of day and a frequency to transmit and monitor as well as a couple of backup freqs.
If you’re in some kind of Red Dawn scenario (great movie, btw), you won’t want to be transmitting from your location or in any pattern of locations. You’ll have to balance your need to communicate with your need for OPSEC and evasion.
If everyone knows the general area where you’ll be, such as a town or a particular forest area, you can agree on very obvious locations to leave messages, such as the top of a very large hill or a unique building, etc. As before, prior commo planning will allow you to leave more accurate messages to your team while not giving away the message (or hopefully that there even is a message).