Smaller and Lighter is Better
This topic comes up occasionally, and it never fails to amaze me how much stuff people carry around just in order to carry around their cameras and lenses, etc. While strollers have some advantages, backpacks seem to me to be unwieldy. They need to be taken off and laid on the ground (not to mention all the packing material some of you seem to use...) where things can get dirty and/or blown away by wind.
I carry a Wista DX, 5 lenses, 6-8 film holders, Pentax Digital Spotmeter, 10+ filters in two sizes, dark cloth, barn doors, exposure record, flashlights, tripod, loupes, 4x glasses, sunglasses and other misc. accessories in a fanny pack, a fly-fishing vest and a small over the shoulder pouch.
I make custom-sized boxes with open tops for the lenses out of corrugated cardboard. Otherwise, things just go in pockets and pouches.
The Wista DX with a lens folded inside goes in the fanny pack along with three other lenses in their home-made cardboard boxes. Also in the fanny pack go two folding pouches with 6 filters each, sizes 52mm and 67mm. One goes in the main compartment with camera and lenses, one in the front zipper pouch. I've got some other stuff in the front zipper pouch as well. The rolled-up dark cloth is strapped onto the outside of the pack.
A short fly-fishing vest carries accessories, viewing filter, flashlight, Pentax meter, cleaning stuff, tape measure, loupe and a bunch of other smaller stuff. The filmholders and exposure notebook along with another small lens goes into a small over-the-shoulder pouch. The tripod goes in a hand, or gets strapped onto the bottom of the fanny pack for scrambling. In rough terrain, I carry a collapsible ski-pole for extra stability and my roofing gloves. Often, I carry a small pair of binoculars and my Garmin GPS as well.
When I set up, nothing has to touch the ground, with the exception of the tripod. I set up the tripod and then hang the filmholder pouch on the center-column tightening knob. The fanny pack has a shoulder strap that I wear cross-body, so when the belt is unbuckled it simply swings to one side and functions as an over-the-shoulder bag; easy to work out of. My meter and viewing filter are tethered to rings on the fly-fishing vest so I can't drop them.
The whole kit weighs in at around 22 lbs. I carry an f/8 SA 90mm, Nikkor W 135mm, Ektar 203mm, Fuji A 240mm and a Nikkor M 300mm for the most part. I alternate in a Fuji SW 75mm at times and leave the 300mm out when I'm anticipating wider views. I usually strap on a bottle of water and toss in a sandwich as well for longer trips unless my beautiful assistant is with me, carrying those things and possibly a lens or two extra :-)
Here's a link to the kit "in action" on the Oregon Coast:
This set-up is good for long day hikes (I've done 20+ miles with it often). When out backpacking, I cut down the kit to 3 lenses, use Mido holders instead and somehow strap everything to my main pack, or get it inside somehow. Then, after "base camp" is set up. I use the reduced-size kit for day excursions.
Since I started carrying this set-up in 1983, I have never damaged a camera or a lens, or anything else for that matter, in transport. I lost a loupe that squeezed its way out of a small pocket in the vest once in a very and scraping descent through a steep ravine; I use a different pocket now... (I did drop my meter once before I decided to tether it on, and I've rolled a polarizer or two down a steep hill from time to time, but these had nothing to do with the carrying...) I worry about slipping and falling backward some time, smashing some gear, but have been lucky so far. Besides, a backpack has the same problem.
I do have a larger internal-frame pack for my Zone VI camera kit which includes more and longer lenses, but I rarely take it on extended trips.
Hope this helps lighten the load somewhat.