Before going to custom, just wondering if there's a plugin with the following features:
We'd like to send a link to calendar where customers can sign up for their pick up date and the amount of product they will be picking (pounds). Ultimately it would be best if the date would become "filled" or "almost filled" when a certain limit is reached (pounds) but we can do that manually each night if need to. And, preferably, we we'd like customer sign ups to be hidden from other customers -- we don't want customers seeing other customers pick ups/amounts.
Thanks so much for your help.
Try the WordPress Editorial Calendar, it enables the user to manage the dates for multiple posts.