Hi,
I walked The Frances in February and will share some experiences which may give you some better idea about your plans.
First of all it was my first Camino so I have nothing to compare it with, and my preparation was very limited.
I used my youth experiences with camping and packing, as well as this site, to help me find a reasonable list of items to bring.
I am a male, mid forties and in decent shape, but for 10 years+ I have not been exercising much.
Just to give you an idea where my advices comes from.
I began to plan my walk about a month before I went and most of my time went into figuring out what to pack. Much information online focuses on the extreme minimum to bring, which of course also means the most expensive items, and I have to say that I went for a balance between cost and items.
This is a rough list of the items I brought:
58 liter Asprey backpack (build in rain cover)
This is considered large or huge by many, but I found its extra space useful in so many ways.
A warm down sleeping bag around -10 celsius (pretty heavy around 1400g but worth it)
1 pair of leather boots
1 pair of hiking pants
1 fleece sweater, good quality
1 fleece jacket to wear under my hard shell jacket
(It is all about layering up and most importantly to stay dry. Dry is the key word)
2 wool underwear shirts
1 pair of wool long sleeve shirt
3 pair of thick wool socks
3 pairs of thin smart socks
2 pair of underpants, cotton but it worked for me
1 wool scarves
1 cap
1 pair of rain trousses
1 pair of light weight jogging trousses
1 pair of sleeping shirt
1 pair of indoor sandals
Toilet and hygiene items, very basic - what else you need you buy on the way ( ear plugs of course..)
1 head lamp
1 pair of wool gloves
1 pair of hard shell mitter gloves
2 reflective straps for legs to be seen in the dark
1 guide book
1 reusable tough plastic bag for grocery, showers etc.
1 brush for cleaning trousses, boots etc.
1 plastic lunch box to store cheese, chorizo and food in
and a few more personal items
All items were in zip bags to keep them dry but I got lucky on an idea I hade before I left.
At camping stores you can buy an 'Airliner backpack bag'.
It's basically a large, strong and water proof bag which one can put the backpack into, to protect the backpack in transit.
I shipped my backpack in the bag and once on the Camino I emptied my backpack, stuffed the bag inside and all my items into the bag.
On my camino I never experienced damp or wet items due to this way of packing.
It doesn't weight much but in my case I walked with a backpack a little heavier than most would recommend.
Between 12 and 15 kilos depending on how much food I brought, water and stuff I picked up on the way. Still it didn't feel as a burden.
Walking the Camino in winter requires warmer and heavier gear.
I can imagine that it is different in many ways from the other seasons but for me it could not have been better.
Day one. Over the Pyrenees. What many people ask about.
The Napoleon was closed so we, our small group of five strangers, were forced to walk the valley and the main road for cars, as all other was snowed in.
It was a very long and hard first day, but at no time did we feel in danger and once in Roncesvalle our first dinner and sleep made up for any of the physically challenges we had encountered.
The locals will assist you and guide you the sane and safe way. Be open. Ask to many questions.
For an example we were give a list of the municipal (town funded and cheap) albergues which were open all the way to Santiago.
This list was not accurate though and we had to improvise many times, but this may be what the Camino really is about. Adapt. Being open. Helping each other.
In winter many municipal albergues are closed.
If your aim is to go for the cheap lodging, and social, you will be forced to walk longer than in other seasons.
In average you have to walk the distances stated in most guide books, around 20-25 kilometers.
The main stopping places, which in winter 2012 were mostly empty.
Many places have blanckets, 3-4 on top of your sleeping bag makes a good bed, as many places lack or have limited heat.
Califacion. Hay califacion en la noche? Are there heat during the night? Is a frequent question at the albergues..
It is all part of walking a winter Camino.
If one gets tired, injured or tired, there are frequent private albergues, hostals, hotels on the way.
A winter camino has no danger to it, as long as one look out for other pilgrims, as they will look out for you.
Food.
I can strongly recommend you to shop powder soups, bred, cheese, fruite and although it weights, you will be grateful for it.
Many times I found myself in an albergue, with only a micro oven, no supermercado around, and one thing is for sure. No one can walk the Camino without food.
Many places there will be restaurantes, menu de peregrino etc. but you cannot depend on it always.
So in short. A winter Camino. It can be snowy, cold, windy, empty landscapes, great friendships, seeing the same people all the way on your walk. Many things.
For me it connected me to people who all had a personal reason to walk at this time. Things that had happend in their lives, people searching for.. something.
I think no one can walk the camino without finding something.
You just have to be in the now and adapt to it.
And remember it so you can implement it into every day life afterward.
Buen Camino