I'm assuming you are setting up a session. In the latest version of TLR, you can almost do what you want.
I'm going to use classic surveyor to describe these steps.
Choose Edit Session then Driver Setup. Assign a driver to the loco you want to use. Add the driver commands you want to be executed. Couple to and drive to track mark.
Save the session changes. In the Train panel, pick the properties tool and click the loco.
In the new dialog that opens, You will see the driver picture and to its right a downward pointing arrow. Click the arrow and choose Show (driver name)
The driver info dialog opens, here you can change the Player Assignment to Automatic Scheduler.
Close the Driver dialog.
Save the changes to the Properties of the loco and save the session.
Exit surveyor and then open the session in Driver.
What should happen is that the commands from Driver Setup should run and complete then dispatcher should issue a task. But while the driver commands do work if you check the assignment of the driver, it is at Player controlled not Automatic scheduler. You can change it manually while the driver commands are running and when finished the driver will be assigned a task by the dispatcher.
So this is a bug. The assignment of the driver set in surveyor is ignored by Driver. You can verify the driver is assigned to the Automatic Scheduler by opening the session in surveyor again and repeating the steps by using the properties tool on the loco again.