A lot of SHTF prepping can depend upon what ‘SHTF’ actually is. In the USA, the sudden calamity tends to be localized, like Katrina. However, even in Katrina it wasn’t a war, and a pump shotgun, hunting rifle, or a handgun was typically more than enough to discourage looters. Did anyone there need many $thousands in weapons and ammo?
For example, one guy put his irreplaceable items (photos, documents, etc) into a backpack, loaded his M1911, and took a bicycle north until he found a bus stop that was still operational. He then took a bus to a regional airport and then caught a flight to relatives.
IMHO, too many survivalists and preppers in the USA spend too much material resources and mental energy prepping to fight a war. Too many are bullet rich and dollar short, or they have lots of ammo, but food and medical has been a secondary priority. If you have the extra cash and a fortress, by all means store what you want if it makes you happy. Just remember that odds are, like most of us here, that you aren’t in military anymore and you don’t have the supply or medical backup the military has. So, taking their approach to things will, at some point, turn into an exercise in futility. For a survivalist or prepper a different approach is needed.
The one SHTF that we know is coming, it’s not speculation, just math at this point, is an economic crash. Those are usually a long, slow, grinding catastrophe, not a sudden, one day or overnight deal. Unless your fortress is absolutely secure economically you might have to relocate as things worsen, and it’s hard to do that with several tons of gear. Do you owe money on your house? Do you rent? If the answer to either is yes, be ready to move if need be.
There are many other events which can also force a relocation, most of them actually. Anything you cannot move in one trip is a wasted resource. So, something to consider is keeping your logistics simple, practical, and workable. Keep your planning low key and sustainable. Defense planning is a given, but food acquisition and replenishment is a much higher priority. Always keep in mind the high possibility of, “What if we have to leave and not come back?”