I think there are some potentially simpler options:

1. If you have connectivity between sites you could look at setting up mirroring and then "failover" to your mirror when everything is caught up.

2. Use backups. The day of your planned cutover get full backups of the existing databases, restore at the new site, apply transaction log backups. At cutover time, take final log backups, take the db's offline, restore the final log backups at the new site and point your apps there.