He should already have a knife (rule #9).
Go re-read where I said my hikes were. My hikes were also a bit longer (4-6 hours depending).
As for why that order: Start with the very basic things that'll keep you safe (and are cheap) and add things that make you safer then add things that make it more enjoyable.
- map and compass: They are dirt cheap, light weight, and don't take up that much room. Being lost without aids without anyone around for many miles sucks and is dangerous.
- boots: comfortable feet and proper support allow you to enjoy the hike and keep going.
- daypack and water bladder: I seriously dislike water bottles on hikes. The best hydration comes from regularly sipping water. For me water bottles don't encourage that behavior and instead encourage infrequent large drinks of water. Daypack holds the bladder, map, and anything else.
- clothes: I didn't really think anything about this until I had them. Hiking in hiking pants is sooooo much nicer than hiking in jeans (and hiking in areas with lots of bushes and mosquito doesn't lend itself to shorts). Having a light wicking shirt is soooooo much nicer than a cotton t-shirt.
- poles: Again, one of those things that you don't think about until you try them. I was so glad to have them for
this trip as I ended up going off trail, over logs, into a boggy area, and going over gaps. The ability to have three points of contact while crossing something where falling would really hurt is extremely helpful.