Yeah, thats a tough one. Youve noted that these days especially, pack makers are emphasizing light weight over super-durability. And thats fine in most casestodays pack fabrics admirably combine toughness with fewer ounces. But they dont do so well being sanded by Red Rock Canyon stone.
So what do to? A few gear makers such as Granite Gear still are banking on the notion that toughness matters. That aptly named companys Precipice ($160) is a 2,800-cubic-inch day pack made with Cordura fabric that can withstand a metric ton of abuse. And its a comfortable, capacious pack that will easily haul the stuff you need.
Another tough pack is Gregorys Z25 ($130). Its smaller than the Granite Gear pack (1,500 cubic inches). But that can be a good thing when trying to squeeze through narrow spaces.
Otherwise, look for packs with the right design and material. Trim and sleek is good, such as both packs above. But also check the fabric specs. The magic number will look something like 210d twill." The 210d" refer to 210 denier," a measure of the thickness of the fibers used. Thinner fibers have higher numbers, 1000d," for instance. That higher number has its advantagesless weight and better water repellency, for instancebut a finer fiber also has less heft. So it resists abrasion less well.
Both the packs I mention are heftier than most fabrics. So check out some packs, ask about the fabric, buy a trim design, and youll be fine.