You can tie dates created in transaction fields to specific tasks on a checklist. Here's how to start:
Go to Fields > Transaction fields > Add field
Select Type: date and enter required data
Go to Checklists > Your template > Action > Add task
Select due before or after
Once you set these preferences on your templates it will ask any user who has added this checklist to their transaction to enter the custom date and they will be reminded of the task due.