I really wish there was some kind of assignment menu for settlers and various tasks. Like you build a noticeboard and there you can assign a settler to a duty like food and they will then be automatically assigned to unassigned crops. You would also be able to see what the settler is assigned to currently. Would also make it much simpler to create and cancel supply routes.
Right now you have to run around to find settlers and then run around to the tasks you wish to assign them to. It's very tedious.