I love it!. I took your idea and added some of my ideas to it, and now we have a cool cave entry gambling area for the server!! 

Very cool prefab that we have been using on all of our recent maps. it doesn't take up much space at all and everything works as intended. There is no height mask included so it does take a little bit of time to get placed without any gaps on the surface, but if you are good in Rust Edit, it won't be an issue. If you are placing this somewhere that causes it to reach below sea level, be sure to place your own water trigger/water culling triggers. Great free prefab to place on any map to offer players a unique little building area.