A few thoughts that you can take or leave:
1. I wouldn't bother with the Canadian flag. These days, Canadians are often more likely to be mocked for doing this than be treated better. And one of the first questions that anyone will ask you when you're talking to them is where you're from, so they'll find out your Canadian soon enough anyway. Just my opinion.
2. Definitely check out both easyjet and ryanair, as they often have flights that are cheaper than the cost of a comparable train ride, and if you're pressed for time and trying to cover a bunch of ground, flying will obviously help you out. For example, if you're flying into London and will be going to Istanbul (I think you said you're interested in going there), consider flying into London and then flying directly to Istanbul. Then meander your way back.
3. Don't have a set itinerary. I've found that the best places I've been to have less to do with the place and more to do with the people I meet. So you don't want to meet a bunch of cool people and then have to take off the next day. Better to be flexible.
4. Have fun and don't sweat the small stuff. Usually when things go a little bit wrong (miss a train; can't get a room for a night and have to sleep in a park), it makes for the best stories.
