Tunnels

One roll to unlock the portcullis. Both roll to lift it manually as there is no functional mechanism to lift it.
Blornvid manages to free the portcullis mechanism and together you barely lift the heavy iron bars before wedging the door pieces to securely hold it up a couple of feet. Crawling under you look around the room. Other that the shattered glass, shattered bottles(?), there is nothing of note. You check the far door before opening it and verify your location. You take a few moments to measure and update the map.

You return to Valpip with the news of another ladder and he sets off to secure the top of it with some guards.

Room 7
You check the door but by now have come to assume these older basic doors are not usually the problem.
After a cursory look you open the door to the next room. A forge with a few smoldering embers in it and an anvil sit in the North-East corner of the room. Someone has scrawled "Beware the light" on the North wall.

Blornvid recognizes signs of this once having been a workshop. Other than the forge and anvil everything else has rotten, rusted, or been taken away.
Give me some rolls or specific directions.
If I keep rolling for you I might accidentally start rolling 1d3 :p :)

Blornvid looks at the forge and wonders why the embers are still warm. The forge is cold and even the ash was been blown out over time. Only a few nuggets with traces of a slow burn somehow remain. It is definitely unusual and beyond his experience as a smith. He instantly assumes magic, spirits, or gods must be involved.

The forge has a magical aura to it though weak

The anvil is finely crafted but you can not discern any special properties. Still, perhaps Mord, the smith, will better be able to tell. He might also have an interest in the forge.

To the south of the room is a porticus and sturdy door. Beyond the porticus is a hallway that opens to the east.