Note: you can use the SQL maintenance to create transaction logs.

The transaction logs generated by SQL every x minutes can vary in file size. It depends on the activity done (number of users/wires/pages/etc.).

Verify how big the transaction logs are, and check the time it takes to copy them to the secondary server. Write down the time.

Also, check the time taken to replicate the volume files. Use the values to tune the frequency of the replication scripts.

If your standard backup procedure already generates the transaction logs, you may add the DR to the list of servers the logs should be transferred to. See: http://msdn.microsoft.com/en-us/library/ms190200.aspx.

For the log shipping as DR solution see: http://sqlmag.com/database-backup-and-recovery/poor-mans-disaster-recovery-use-log-shipping-sql-server-your-own-risk.

And for an overview of possible (and more expensive) alternatives, see: http://technet.microsoft.com/en-us/library/hh393576(v=sql.110).aspx.