Ok so I am an avid walk in hunter as well.
I usually take:
at least 2 dozen decoys
parka (in my pack)
2-3 boxes of shells
a couple Gatorades
first aid kit
extra decoy string/weights
Shotgun (on pack if wanted)
A few years ago I bought a Sportsman's Outdoor Products Elite Blind Pack. This thing rocks. I will never try to carry a bag over one shoulder ever again. It is a well built backpack that is comfortable with plenty of weight. It comes with a decoy bag that attaches right to the pack and can hold 3 dozen decoys, it is so much nicer to have nice backpack shoulder straps than to have those nylon decoy bag straps digging in to you for a couple miles.
This pack has 2 front pockets specifically designed to hold up to 4 boxes of shotgun shells, a large main pocket that will hold all of you large gear like your extra clothing and coat, inside of the top of the main pocket there is a few smaller pockets with zippers and some mesh pouches with bungee nylon to hold all of your small items like phone, GPS, wallet or hand warmers and such. There is one more pocket on the lid flap where I stash all of my calls, knife, headlamp and sunglasses.
This pack also has the ability to haul your shotgun. When it is a couple hours before shooting light and you have a long walk through mud and water it is amazing how much better you can keep your balance when you don't have to worry about your shotgun slipping off your shoulder down into the mud.
I would strongly suggest looking into these packs. I will never go back to anything else. Sportsman's Outdoor Products is MADE IN THE USA and they stand behind their products. If you EVER have a problem they will help you out forever!http://sophuntinggear.com/products/?rou ... turer_id=5
I have not failed. I have just found 10,000 ways that don't work.