There didn't seem to be a forum for this kind of question, so hopefully somebody with the right info can help out.
First off, I'm getting to be an old phart. For years I stuck with ALICE gear. I went to a civilian militia event once and I was one of three guys still carrying ALICE stuff. But, it's uncomfortable; its' cumbersome; it's ridiculous. You have a belt with suspenders - the equivalent of a modern "battle belt." Then you put a pack on over the top of that. So, you essentially have two sets of straps going over your shoulders and on top of that, you use a rifle sling.
We can now take a step up and have a plate carrier OR places want to sell you a chest rig- in which case you still need to have something on your back to carry water and essentials. So, you have a chest rig and a back pack... and two sets of straps coming across your shoulders, PLUS a rifle sling.
Back to the plate carrier. At 64, I'm not thinking about 17 pounds of plates front and back, plus a cumberbund holding two smaller plates, ammo, magazines, and probably a battle belt plus sidearm and your rifle OMG. I have a MOLLE fanny pack that a dealer said is hard to come by. So, what would be the downside to a plate carrier, no plates, ammo in front (3 mags), water bladder in the pocket on the back side of the plate carrier, and my fanny pack. It would serve as a kind of Bug Out Bag and get out of a riot, looter scenario. Anyone with any better ideas?