OpenWRT should have VLAN support out of the gate. Probably has an admin page for it.
Unless you want to go full wireless I would strongly suggest at least one USB ethernet dongle and a cheap managed switch (managed so you can take advangate of VLANs. Unmanaged switches are cheaper if you decide VLANs aren’t for you).
The real captains logs are the voice notes you make to yourself on the toilet.