Yup, you are doing it correctly... CRA are used extensively in the 5000 (and Axxess, and prior Inter-Tel products) for routing calls in the system, hence the name CALL ROUTING Announcement. Just remove all the greetings and set the timeout to the destination you want. I have systems out there with 30, 40, and even 50 different CRAs for various purposes.
Also remember that STAR applications will always search from the top down and route to the first match, not the "most correct" one... so if you have a Saturday route in position 5 and a April 13 route position 6, on Saturday, April 13, the call will follow the Saturday route. Always put the most specific rules at the top, skip a few lines, then more general rules, and put the least restrictive route towards the bottom.