I would love to see integration with TouchStay. We currently have an email template that sends guests the link for the digital guidebook. However, we can't include the door code in Touchstay since we don't want them to have access to that until the day of arrival. There is no way to limit access to certain areas of it if the guide book is sent as a link. I can't remember why but that's what TouchStay told us.
Yep, we're in talks with them, but waiting for them to build an API before we can do integration other than the email stuff you're using now.