Enterprise D's Deck 1-Lower - what's it like?

The closest I know of is Stage 9's Virtual Enterprise-D, which was cancelled due to a cease & desist letter from Paramount. It was a reproduction of the Enterprise-D, including many areas only partially seen, such as crew quarters, the main shuttlebay, and the connective areas of Deck 1.

Although this game/simulation can't be legally acquired anymore, there are a few videos of people who had played it. I've queued up one such video to the point where the player leave the bridge toward the observation deck. You can see the entrance to Deck 1 Lower, but unfortunately it's inaccessible as it was never developed before the project was shut down.

We see a brief scene of the underside of deck 1 in the TNG episode, Brothers.

Data takes control of the Enterprise and locks everyone out of the bridge. Two of the crew attempt to enter the bridge through an access panel on the bottom of deck 1. They are thwarted when Data creates a force-field at the access panel.

Not sure if this is quite what you want since it shows briefly what is just below deck 1 rather than other rooms and corridors on deck 1.

All most all that stuff on the blueprints is behind bulkheads and are not common traffic areas. They are full of computers and machines and such.

For the most part Deck 1 is the Bridge, the Observation Lounge and the Captain's ready room. We sure have never seen the Communication Office or the Stairs.