Today I decided that, given it was 15 outside with 15" of snow, it'd be a good time to do a practice run of what I plan to take to Alaska for my "airplane kit." Off to the local state park for an invigorating 2 mile hike!

In my daypack:
20-degree down sleeping bag
1 Liter titanium pot
MSR Whisperlite stove, with 350ml can of isopropane
GI poncho
NorthFace jacket... forget the name, but about the warmth of a
fleece jacket
"odds and ends" - knife, whistle, etc. The basic 10 Essentials

On me:
my PSK
my new Leatherman (thank you, girlfriend!)
my Benchmade Griptilian

I'm wearing:
Smartwool cap, under my Bailey "cowboy" hat
Nike winter-weight workout shirt
NF Hyvent shell
Running tights
BDU Pants
BDU ECWCS gore-tex pants
wool socks
Eddie Baur winter boots.
EMS glove liners, wool gloves, OP glove shells

Observations:
- it's actually easier to trudge through the snow than walk on the path made by XC skiiers. Not as much slipping.
- 15 is cold! Until you move, then somehow you sweat (I don't get it!)
-15 degrees gets cold real quick when you stop for lunch.
-A "dump bag" on your hip is a good idea. It would have been nice to take my hat or gloves off for a few minutes and not have to carry the items.
- 2 miles takes a while in snow. And works muscles not normally used in hiking. Lots more calf muscle than I would have expected.
- Civilian "MREs" aren't as user-friendly as the real kind. Amazing, huh?
-Snow boils fairly quickly.
- I could have used something to insulate my butt, besides my sleeping bag, during lunch.
-I was suprised how well the ECWCS pants did on keeping snow out of my boots and socks - the boots are only about as tall as a pair of hi-top basketball shoes

One thing I'd like to throw open for opinions. I was debating shelter options in this kit. I was initially hoping to take my 1-man tent and my 20 degree bag. While they both fit in this daypack, there isn't much room for anything else. I was also hoping to throw in a poncho-liner with my poncho, as both a sleeping layer, something to wear while hiking if it gets real cold, a ground pad when I stop, or a last ditch shelter. But, with this bag, I can't fit all 4 of those items. So do you you think I should:
A) leave the sleeping bag behind
B) Leave the tent behind
C) Leave the poncho and liner behind, and just deal with the lack of space in the backpack
D) buy a new backpack!

I'm personally leaning towards D, just guz I'm a gear [censored]. But the price is pretty taxing right now. Any thoughts on this?

Is it possible to strap the sleeping bag to the outside of the backpack?

A few compression straps and anything can be secured to a pack. Could you not secure the sleeping bag to the bottom of the pack?

As for being too warm and sweating, judging by the amount of clothes you were wearing, this does not surprise me. 15 F is equivalent to roughly 9 C. Near this temperature which we experienced yesterday while out hiking, both of us only had a lightweight long sleeved shirt, windbreaker, lightweight running tights and one pair of pants. We were warm but not overly. Granted once we stopped for any length of time, out came a sweater and toque.

My dump bag is my jacket, which has almost armpit to waist inside pockets that fits extra gear, mitts and a toque.

A small 18 to 24 inch piece of fleece folded in half makes an idea butt insulator and has other uses as well if and when needed. This small size also makes for any easy fit in the pack.

Alaska? Start with a parka.

Alaska is cold but in a lot of areas it is no colder and in fact warmer in winter then some other states are. It really depends on where you are going and your activity levels in Alaska that will dictate your clothing requirements.

I have been looking at the temps where I'll be staying. It's actually been low 30s this past week, while we in MI have been, oh... hovering around 0. I have a down parka, but think that it'll probably be overkill. I will, however, be packing it and wearing it around town.

This daypack doesn't have much outside attatchment points. I might be able to juryrig something, but honestly, I'd rather put the tent outside. The sleeping bag IS down, after all. I might go buy a drysack for it too, just to be safe.

I realize I wore too much. Actually, the top was fine. My legs were a bit damp, so next time I'll ditch the BDU pants, and just keep the tights under the gore-tex. And carry a pair of ear warmers in addition to the wool cap.

Good idea on the fleece. I'll check the local fabric shop and maybe they can help me add some nylon to one side.

As for the jacket, Sherpadog, this jacket only has "handwarmer" not "napoleon" style pockets. Unfortunately. I do have a jacket like that, but it's a rain jacket that has seriously lost it's DWR, despite repeated re-applications.

Like I said, this has been kind of a trial-by-fire on what I'm packing for aircraft egress. I figure the clothing day-to-day I have figured out, but I'm trying to figure how much I would need for a trek in the snow. By figuring what I need, I can add that to the bag and plan on my "normal" clothes being the starting point.

OK. My 2 cents worth.

A couple of extra pairs of dry socks and gloves.
You can hang a damp pair on your bag to dry as you wear a dry pair
Heavy duty garbage bags make decent dry bags if you double bag them.
Strip down when moving, dress up when stopped.

You might need a bigger bag, winter gear is about bulk. You end up packing a lot of air even with compression straps.
It is nice to be able to stuff your coat into the bag too when you are hiking.

Yes, slogging through snow is exhausting.
Remember to take frequent breaks.

Edit:
I like to point out that mitts are warmer than gloves and an extra large pair lets you wear gloves inside them of you have to.

Edit again.
Goretex still sweats, just not as badly as a fully sealed fabric would. I would suggest gaiters to keep your calves dry if the snow is wet and breathable wind pants over decent long underwear instead of goretex.
Fleece is good for underwear, especially since good woolens are impossible to buy any more.

Sherpadog suggested fleece as a sit down pad.
I like a piece of ensolite, I will have to try some scrap fleece next time I am out, it sounds like a good idea.

Most people overdress the upper body and underdress the lower body. If you have decent lower body clothing you might find yourself hiking in your tee shirt just to stay comfortable.

A piece of closed cell foam sleeping pad makes a great place to sit. I've even seen people cut a small piece, and attach it like a flap on the bottom of their pack, so when they sit, it's under their butt. It just hangs there when hiking. A pad is good for glissading... which is fun, but, better have an ice axe to self arrest if you get going too fast.

Those closed cell foam pads are also handy if you need to splint an arm or leg. Oh yeah, you can even sleep on them. I think some kind of pad is a must in winter, you really need some insulation under the sleeping bag or it's going to be a cooooold night.

Sorry...forgot about the down bag. By the sounds of it, you need a new backpack....but don't take my word for it as I what seems to be a backpack obsession. Today I was ogling a new pack even though I just purchased another one a couple of weeks ago.

As for the glove issue, remember when you were a kid and you had gloves that were attached by a string? Just saying...explore all possibilities.

Remember; layers work on EVERY part of your body; head, hands, torso, legs. Best to start off cool, and warm up. Winter hiking is all about moderating your core; dont sweat. If you're overheating, remove a layer. If you're still overheating, slow down. When you stop, don hat & jacket.
Layer your hands too. I go with a thin glove liner, a set of ragg wool half gloves, with the top that folds over to make them mittens, then an outer OR nylon mitt (they make them in goretex, but, the hands dont sweat enough, dont fall into that trap. Waterproof nylon is all you need). I am doing some extended snowshoeing tomorrow, testing out some gear, and its supposed to be in the mid 20's. I am carrying alot of extra clothing, but will likely not wear it unless I am standing still.