Winter in Europe

If you make it to Spain then heading south to Andalucia region will be less cold and fairly cheap for backpackers viz. Seville, Granada, Cordoba, Cadiz (and maybe Malaga - should not be overrun with Brits in winter). Lots if cheap food and wine, super friendly people and interesting architecture.

Re: European winter. Layering is the way to go plus a good windproof/rainproof jacket. I suggest you go to a good camping store like Kathmandu to get quality merino wool base/mid/top layers. Scarf, beanie, woolen socks and sturdy boots also a must.

Hi

In terms of Belgium I would suggest skipping Brussels and instead adding Ghent as well as going to Bruges. Ghent's quite magical, it's got all the historic bits but is far less touristy than Bruges. My friend and I were there in February this year, very cold but also brilliant fun! We found Brussels to be very cold and bleak, with all the main sights quite spread out through the city. Good luck :)

Living in Brussels and having lived in Ghent for five years as a student, I wouldn't want to choose between both cities. Brussels is interesting as European capital and because of the fact that northern European culture meets southern European culture and many African cultures. Ghent is a little prettier (i.e. clean, as in 'not a capital'), but also a little less spectacular. Smaller, less tourists, less trouble. Don't worry too much about the choice. You can do either city in one day. Note that there is one train line you'll love: Leuven - Brussels - Ghent - Bruges - Ostende. All equally interesting places only 30 minutes apart.

That said I really believe the way too political discussion of Belgium on the Lonely Planet website is journal talk or quite elitist. In reality, people don't care that much, they focus on their families as anywhere else. You'll find out.

Is it actually easy to find accommodation in Germany around Christmas?

Germany is a big place.

Would any of these places ..

I wouldn't want to give guarantees one way or the other. My experience is that there is always accommodation for transients, people who are in one day and out the next. This 'layer' of travel dynamic generally slips under the radar of hotel booking sites, and even goes unnoticed by people planning weekend getaways, 1-2 week holidays and so on.
You can go to most middle to large cities, and even small towns, step out of the train station and see 'hotel' signs within 100m. There are always hotels near train stations: they're there for a reason. May not be the nicest rooms or best part of town .. you'll likely find a tourist office which offers assistance in finding rooms. The infrastructrure that was in place before internet is still there.

You may develop a feel for this once you're on the road. I'm prepared to take what I can find - if only for a night. A guidebook plus map gives me ideas about where to look for budget accom. Then I go hunt - not an issue in the bigger cities.

If your tolerance for uncertainty/unpredictability is lower, then you can always book ahead, just to ease your mind. There's no point worrying about it. I have no problem with booking ahead if I know where I'm going and when. I'll need a room sooner or later, why not sooner if I don't set a priority on flexibility?

Munich to Paris

I'd expect there would be an overnight train with couchettes.
Check http://www.bahn.de/i/view/DEU/en/index.shtml there might be early booking promotion fares as well

Better to post the Spain and Scotland questions as separate threads (Scotland on appropriate branch)

If I err on the side of less is it possible to get appropriate warm clothes over there?

Of course. The people who live here like to keep warm. Street markets are always a place for cheap throw-away clothes.
As far as layering is concerned, backpackers do it because they're likely to be travelling through large temperature differences and don't want a heavy coat when they're around the warmer Mediterranean area. Usually, a lined waist-level jacket is enough, combined with t-shirt, shirt, sweater/fleece, and scarf/hat is enough for the more extreme cold temperatures. You I prefer a fleece with zip front because it also passes for the outer layer 'jacket' if it's warm enough. Small lightweight windbreaker is also good insulation and not much space taken in the pack. Possibly one set thermal underwear, just in case.

Andalucia sounds wonderful, is it difficult to drive around there?

In the countryside - no.
In the city, very difficult and a car is not recommended; lots of very narrow, windy - not gusty but winding ;-) one way streets.

As you will be in Europe during mid winter I believe that being warm is of utmost important. As you are from Perth, I don't think you know what being really cold is like! When I was there in late Autumn 2008, it was super cold and even with triple layer wool, beanie, scarf and snow jacket it was still a struggle to keep warm some days. Quality clothing will last for many years and a good investment if you intend on travelling to other cold places. If not, sure, get away with the cheaper line of clothing and buy some if you need to while you are in Europe. As I do 4WDing and camping around the Snowy Mountains I have invested in proper gear.

Re: Scotland - rent a car and drive the Whisky trail. Fly into either Glasgow or Edinburgh and head up Speyside. Highly recommend Abalour, Glenfiddich, Glenlivet and Macallan. Even if you don't like whisky, the scenery is fantastic.

Good luck and happy travels.