There's a book that changed my thinking a little called "Strategic Relocation," where the main thread throughout the book is that holding up in your home-as-castle does not give you the best odds for survival, which is what the ultimate goal is. Everyone has a different starting situation, but for many, the concept of being off-grid or innawoods is in direct opposition with how we make a living for our families. We live in populated areas, which are generally less safe in a crisis than self-sufficiently isolated.
You don't need the book to give you the answers. It's good for a read, but not necessary if you find that planning for strategic relocation agrees with you. If you're in a metro area, have the means to protect yourself while you execute your relocation plan to your next stronghold/cache, in all likelihood is a safe spot to regroup, maybe waiting for remote family members, and then relocate to some place more isolated with your supplies.
It's not about having 3 houses. It might be your metro apartment, where you make your wages, and a storage facility that is on the way to a rural relative who is like-minded.
For sure, have your 9mm/.40SW/.45 or whatever you want. You'll likely want a shotgun of some sort. I don't think the utility of a .22LR with a scope can be overstated, though. You might not think it's your man-hunter, but you can buy rounds by the bucket and it's good for small game. I don't want to be on the receiving end of a well placed .22LR.
I think you also do a rational assessment of where you are living. Online crime maps can give you a real picture of the neighborhood (assuming bigger cities). Get to know who your sheriff is. You don't have to meet him/her, but understand what they stand for.