If you value sleep and vicinity to elk over the creature comforts of basecamp, bivy hunting is the way to go, but like others have said, you want to be sure you've practiced your systems before you ruin your hunt. Some folks just simply can't get comfortable dropping camp in an ultralight style. You're also likely carrying 10-20 lbs more in your pack on a daily basis, with camp gear and food.
I'm not sure that I would bivy hunt if the ultralight backpacking side wasn't on autopilot for me.
I agree completely on the pack shape. Also, I'm a big believer that an extra pound or two in the frame will result in a much lighter carry under big weight. I skimped on pack frames for years coming from that ethos in alpine climbing, but I converted about 5 years ago and won't go back.
There are a bunch of threads on this, but if it's helpful, my bivy hunt setup for September elk in Colorado is this ...
Yes, that's a terrible photo, but it gives you the idea.
Shelter: For less than 3 nights I'll use my 15-year-old Bibler (now Black Diamond) Hoop Bivy under a 10x8 Ultralite Guide tarp from Brooks Range, which I usually hang with my two trekking poles, with a long end sheltering from the windward side. If 3 nights or more, I'll add (if rain/cold are in the forecast) or sub a floorless pyramid. I've been using the Hyperlite Ultamid lately. The hoop bivy has the thin wire to keep the bag off your face without the added weight of poles.
Bag: Western Mountaineering Versalite with a 3oz overfill (a little overkill for most September nights, but sub 2.5 lbs and roughly 0F rated with the overfill). This was the best bag on the market for dry climates when I bought it in 2006 and I believe it's the same today.
Pad: Exped SynMat UL (that I won at a Backcountry Hunters & Anglers event!)
Cook: Primus Lite+ stove and a titanium spork (I usually eat one 2-serving Mountain House for dinner, a protein mix and Bobo's Bar for breakfast, and a mix of bars, Justin's nut butter squeezes, dehydrated fruit, and Snicker's throughout the day.
Water: Adventure Medical RapidPure Trailblazer gravity purifier or Grayl. I've been using the gravity purifier more lately for convenience in camp, though it weighs almost twice as much (18.5 oz vs. 10.9 oz) and isn't as convenient when on the move.
I also usually carry a small, inflatable solar lantern to give me stationary light. You can see it hanging from the end of the tarp.
I store my pack under the shelter with the rain cover on in case we get precip overnight.
I can go from full pack to fully set-up camp in about 5 minutes, including hanging the tarp and filling my pad. Again, if I were concerned about fiddling with my camp setup in the field, I would very likely not mess with it.
Also, for my money, the Salomon Quest 4D boots are hard to beat for medium-to-narrow width feet.
Disclaimer, I work with Salomon, Adventure Medical and Primus, but chose their gear before that was the case.
