I spent an hour on one game trying to beat crazy europe. I don't want to start another unless I know what the best strategy is going in. Last time I tried to hold the enemy off of northern scotland and invade from southern brittan into spain and though it was a good long battle, I was soundly beaten eventually. Someone correct my strategy, should I help my team mate offensively and just try to protect the border of Southern Brittan? HELP!

try airlifting the 120s to your ally and you will find it alot easier

From what i hear lots of people are playing Europe challenge with airlifting support to the AI ally. I advise you to try different approach- do not send reinforcements to your ally, use them to break through your enemy defenses in France and follow a two tier strategy afterwards:
1.with a massive army move continuously (by the shortest route) towards enemy's heartland(do not use this army to secure bonuses;move it as fast as possible) with the goal of reaching Lutsk in Ukraine before your ally is defeated.
After reaching Lutsk (or even sooner) you should attack in many directions at the same time, and try to break as many of enemy bonuses as possible.
2.When possible try to conquer the French bonus and others afterwards.

This strategy might be harder to implement but has one great advantage: you are not relaying on the AI's ability to use your reinforcements properly.Also you will learn a lot more about the mechanics of the game and you will win the challenge in historically slightly more accurate way.

I just attacked into France and then split off into every territory I could hit each time...
Airlifted the first reinforcements in to help me break resistance in Southern France, second set went into Scotland when the enemy got close in Norway...

My technique was just to expand as fast as possible taking every territory along the way, splitting my blocks of troops down as the frontier grows...

The last 2 times I've played it I won with my ally still alive :D

the first time I played it, I sent all my reinforcements to myself, and focused on expanding as fast as possible.. I managed to win in 1 turn over the star ranking.. I haven't managed to get close to matching it since and IDK why.. If i recall, my ally managed to hold his own the first time I played *unusually* so I had an easy time of it..

I've beat it both ways. I think the fastest time I sent the first 2 reinforcements to Russia and kept the 3rd one for me. But it works either way.

I reinforce my dumbass teammate early by transfer into Norway and by air in the far north east part of the board, preferrably where I know the opponent is going to attack with a large force. I try to avoid reinforcing my teammate in the center of the map because then I'll have to plow through his retarded ass later to get to the enemy, which will cost lots of extra turns. The best finish will end closer to the middle of the map because it will take fewer turns to get there. Take a peek at your teammate's idiotic orders before each turn and update your strategy accordingly. Don't step into any bonus you expect him to complete because he'll stupidly reinforce your position rather than attacking it. When nearing the end of the game, relentlessly attack your teammate to surround the enemy with your armies because your teammate will always make sure the enemy has a way out of even the most hopeless situation.

Oh, and if you've only invested an hour, you're doing a lot better than I am.