I think, the first casting of MMM always needs a dedicated scene where the rest of the party get to explore what the wizard has made for them. It's a massive opportunity for creativity with the players, and as a DM you can just take a load off and let the wizard player run the session for a while, explaining all the cool things they incorporated.
The first time I cast MMM in 5e, it was with my pyrophobic gnome librarian wizard, Neff. She build a special room for each member of the party to cater to their needs, and I built a map for it (we were on VTT)