It's used, and I assume it is a discontinued model. (I see no reason to purchase a new backpack when, as you pointed out, they last for thousands of miles).
They only last thousands of miles when constructed well.
I "dog" my dog's Kelty pack because the zippers aren't as nice as those on my REI bags, the buckles feel more brittle and the stitching is not double-reinforced like on my nicer packs. You want self-repairing zippers. You want strong reinforcement of the straps to the pack fabric. You want adjustable height for the shoulder strap anchor. You want a good padded waist belt.
Maybe Kelty has changed in the last 8 years... that's how long it has been since I've bought a pack other than the 1 I have for my dog.
2 weeks of hiking means a bigazz pack. 6000ci or so. No point carrying a bunch of clothes, because you're going to be doing laundry in creeks and such anyways. And 2 weeks worth of food... that means freeze dried or a fishing pole and a lot of reliance on good catches, or bunnies, or foraging somehow.
Considering your wife is coming too... freeze dried stuff.
At 3 packets per day + snacks (GORP, trail mix, granola bars, whatever) that comes out to 30 to 42 food packets to carry. And that's eating light. Call it 50, for an emergency buffer and to break monotany. Mountain House single serving stuff weighs about 4 ounces, so double serving stuff probably weighs about 8. That's 25 pounds of food @ 50 packets.
If each of you carried 25 of those packets, that's 12 pounds each and approximately 1/3 to 1/2 of your total internal pack capacity.
(Frankly, I've never done a trip > 4 days that I didn't forage somehow... usually fish and fruit. That freeze dried stuff gets REALLY old after awhile. Bring a fishing pole.)
Then you've got all the gear for 2 weeks in the wild. Pack's gonna be bursting at the seams.
You'll want lots of places to strap stuff to the exterior. Good candidate gear for outside the pack are sleep pad, tent (not the sleeping bag though: you want that dry at all costs), hatchet, water, cook gear, places to hang clothes to dry, quick access to snacks and first aid stuff.
Of course, that same 6000ci pack absolutely sucks for a 2-3 day hike. Gear gets floppy in it unless you get really creative with cinch straps and bungee cords. That's why 3500ci packs exist.
If you're not serious about a long trek, I'd suggest you stick closer to that size. You'll get better use out of it and enjoy them more.
