Machka:

I think a large part of your problems stem from the fact that you're trying to lug a full size bicycle and this limits your options overall. If I traveled as much as you do, I would seriously look at getting a travel folding bicycle like Bike Friday. I don't work for the company and have less expensive Dahon bicycles but it seems to me this would really make your life a lot easier than lugging a bicycle box around an airport or train station.

Yes, but I wonder about the comfort of that type of bicycle for long Randonneuring events like 1200K randonnees. Those are the types of events I travel for ... the touring I do before and after those events is just an added bonus.

I've taken a bike with pedals from Montreal to Windsor on VIA Rail with no problems at all.

A tip for taking bikes on greyhounds (in canada). They state that a box is required, and I've been shown the page in their policy manual that says so. However, really they just want it to be self-contained and have no chance of damaging other passengers' stuff. An option for when you can't find a box is to use shrink wrap (the industrial kind). Every big box store (cdn tires are ubiquitous) will have it. Slap a few pieces of cardboard around your bike and wrap the whole thing until it looks like a mummy (empty panniers work well as padding too). Also, there's little need to remove the pedals, which is usually required for a box.

Transporting a bike is a pain. I just got back from a cross-country tour that due to injury was half biking and half bussing/hitchhiking/flying. The latter were a major pain.