Think back to your 68 Whisky days for the items in your M3 or M5 bag that were lightweight, multi-use, and commonly used during FTX.
Definitely a small piece of moleskin, since someone in a group always has a brainfart and wears a set of boots that aren't broken in, a nasty bunch of blisters will slow down their hike and could get infected in the field.
A standard issue "Drive on rag" aka Triangular Muslin Cravat bandage gets used a lot. Trips and falls occur commonly, so you may need it to make an arm sling with it. It is still a bandage should you need to pack a deep wound. Heat casualties are common, so a wet Drive on rag over the head helps. And the list of uses goes on and on for that small, light and simple piece of equipment.
By SOP, all my 18D's kept a small headlamp in their aid bag, I am assuming 68W's did the same. Pretty hard to remove a splinter (or treat a gunshot wound for that matter) at night without a headlamp. Your a civ now, so no need for a red light, just a plain white light is fine.
A couple Benadryl tablets is a must, never know if someone is going to be affected heavily by an allergic reaction or a scorpion sting.
Don't go overboard, just think back to your training and experience and bring what you think you will need.