Enrolment

Hi, I'm trying to work out best practice for setting up our moodle eLearning server. I have set up moodle 1.9 with LDAP for all LDAP users. We use an access database for our class enrolment data. I think the best way to set up the enrolment is via a flat file which is created from the access database, but this would require all the users to already be created within the system. I would like to create a course for every subject/class.
I could create a mysql script that would create the necessary data for the mdl_user table (and any others needed) and set the 'auth' column of mdl_user to 'ldap'. Then I could auto-enrol all students.
I think I would need to check the last used user creation script against the current one to add/remove any users. I would also need to do the same for enrolment in the classes.

Is this the right? Are there some sample scripts that could help in this area?

Any advice, gratefully welcome.

Rob