Oddly, every time that I have won on that map was when I did not start in the west - either team or ffa.
The west *looks* impressive, but that's because the territories are large. Ultimately, though, they just don't add up.
The best strategy I've found is to create a base and then scatter a bunch of scouts out & about. For example, this game:
http://warlight.net/MultiPlayer.aspx?GameID=1133725. I started with a base in South Carolina and scouts in Colorado, Illinois, Michigan & WV. If you look at turn 26, you'll see that Therv had the West & Northwest, while I had the center & a chunk of the Southeast. I had more than twice the armies that therv had and was able to crush most of his big bonuses while mine were protected. In fact, even if they had all ganged up on me at that point, I outnumbered them and could break them more quickly & easily than they could break me.
Here's a (currently running, but not fogged) example of the West vs the East:
http://warlight.net/MultiPlayer.aspx?GameID=1112650. It's a FFA but a strong early alliance/rivalry developed between the east & the west (and then folks got booted & surrendered... it's all rather ugly). Tonkafun has the west now and looks huge, but the reality is that he's only slightly larger DeadlyAzn (who is poised to pick up two more states in the next couple of turns which will tip that balance) and smaller than I am. Will he win? Perhaps... the diplo cards last 5 turns and if he plays them on the eastern alliance, that will force them (us) to fight and who knows what that will look like.