Mandy's run a few adventures she made up, but no dungeons. I made Mandy a little My First Dungeon Kit. So she can fill it in, change it around as she likes, run people through it, realize it's easy and then make her own. Not the world's most ambitious dungeon, but there's enough there for the PCs to have lots of options about what to do and have some fun before getting to the major encounters and/or treasure. Click to enlarge the starter dungeon.
The thing underneath is just something I'm drawing. You can use it as mysterious glyphs or as the plan of an ancient city, or both. Whatever.