"My understanding is that trails can be closed/shut down much easier than roads. Might ask about that."
I am not sure, the next time I talk to him I will ask. I suppose that could be the case as trails would be considered unnecessary for travel. However most of the roads that would get classified as trails are Level 2 Roads which are typically local roads that are connectors and for high clearance vehicles which I think the FS can already close pretty easily, at least on a temporary basis.
One thing he did mention is that when a road is damaged and needs to be closed it is more difficult to get it repaired and reopened due to engineering department having to get involved to make sure the repairs meet the construction standard. This would not necessarily be the case with a trail.