You could post on different realm forums to help have a guild lined up, that's willing to take you in when you 60 for raiding if you're looking to raid. They might even help the leveling process, if you're interested in receiving help. This way you can pick a role with some comfort of a home. If you're just looking to level, dungeon, or other things outside of raiding then that's a little less important.
The population census data isn't as accurate as it use to be, and it wasn't ever 100% accurate anyways but held a good idea of population for each server. You can use this to help narrow it down to a few servers to begin your search on.