I believe we can solve the food issues without compromising the existing system with two fairly simple changes:
One, allow lords to create (but not accept) trade postings while away. This way they do not have to stay at home, but to complete a trade it needs either someone staying at home or a trader. The whole realm could be away on a war with a few traders back home brokering all the trade deals the lords post.
Two, allow lords to post future trades. In addition to an end date, you can also give them a start date. For simplicity, one to four weeks in the future. That way, you can deal with food once a month and be done with it.
This would allow for the usual recipe of making things less hassle but if you invest the time to micro-manage, there's a small advantage in it. And it would still require intentional actions instead of automation and "not my problem".
If they have the option for how many weeks an order will remain - wouldn't they most likely pick the longest duration possible? It's in their favor to do so.
