Pretty much everything @David323 said. This is the Alamo, the last stand. If things are so bad that I/we have to bug out from here, it’s over.
Folks in the city or suburbs, I don’t envy. If you’re in this camp, start now and find someone in a rural area, WELL IN ADVANCE and reach out to them to be part of their group. Start a conversation. Offer to help build, improve, or cache stuff there. Don’t just show up, even if it’s a mild acquaintance from work or whatnot.
Things to bring. A skill or trade. This would be the most important thing to bring. Most preppers have all the “stuff” they need. That is why they are preppers. Similar to David, people assets are in short supply. Quality of character and trained in something are the most important skill sets.
Examples of skills that would be needed: Muscle (ability to do manual labor), gardening, teaching, ministry, sewing, medical, dentistry, animal husbandry, gardening, blacksmithing, carpentry, tree felling, hunting, field dressing, security tactical ops, HAM/com, leather work, swimming, fishing, entertainment, solar array maintenance, well maintenance, veterinarian… Believe it or not old age does not disqualify you. Old folks have an extraordinary amount of wisdom, teaching, story telling, inspirational, bringing that ray of sunshine for mental stability.
Things that would hurt your ability to be welcomed: Smoker, maintenance meds, over weight, drinker, no skills, but the worst thing, a bad attitude or bad character. A person with a bad character is generally something that can’t be taught. All the other skills needed generally can be taught.
Of course it would really help your case for acceptance if you showed up with a car/truck full of supplies.