I use Heat Factory Foot Warmers-- insoles that hold the disposable hand warmers. They work great.

Also, since you will likely be sitting all day, consider a pair of boot blankets.

Here's a link to the insoles. They cut to fit and use any of the regular size hand warmers that you can get anywhere.

http://www.wardrobesupplies.com/store/bodywarm.html

I had a buddy that went and he said they put you out ALL day. He said that the drinks he brought with him froze before he got to drink them. I would pack a thermous. It may sound funny but maybe an ice chest just to keep the cold out. Maybe a blanket. If you hunting an indian reserve they may put you on the ground.

I would definitely invest in a Heater Body Suit....

Ive never been but Ive been told that you have to have the bolt of your gun oil free or it will freeze the firing pin.

...'Big Sam left Seattle in 'da year of '92'...might be best for us softee'e to go in 'da 'Good Old Summer Time' !!!...cheer/cheers