I'm not sure this applicable here though. I'm not trying to get vlans out on different ports. Just tagged and untagged packets on one (or all) LAN ports.
The gui has a vlan tagging feature on the setup/networking page so I assume some tagging is possible, just not port based.
If I could manage to at least get the port to accept packets on vlan 1000 I could see them with tcpdump and go from there. So far no luck.
An alternative for me would be to get the main internet feed and the guest internet feed out on separate ports on the WNDR3700v4. I could then make a tagged 802.1q trunk of them in the GS110TP that feeds the house with the down side of wasting one GS110TP port.