If the users have to scroll to the date, I probably would set up cascading combos. I have combos with a couple of thousand items, but users always type in the value they want as they have it on a paper form in front of them. I use a combo to get other columns of data.
I've done it (make filtering selections) both on a form before the actual work form and on the actual work form. I'd say it depends on your desired workflow.