Can we have two different grids? Can we show the downstairs rooms visited when downstairs and the upstairs rooms visited when upstairs?

If you mean using the default gridmap, it should show a faint overlay of rooms that are on a different level. But this only works if you use exits that inherit the updirection and downdirection types.

I believe there's an explanation for how to deal with other situations on the help pages.

I used in and out, but are those not separate levels of a kind, too? I think there should be a way to show the grid at some times and not other times, and also differentiate one floor from another. I would even add extra script to clarify where every room is if I knew how, so that teleporting into a room would not slide the yellow dot off into no man's land instead of placing him into the square that once, but no longer, would (and always should) represent the room the player is teleporting into.
I doubt it would be easy to explain to me, but it could really work. I still think it could be built-in, maybe in an upgrade, one day.
Meanwhile, thank you for reminding me to switch to up and down over in and out. I also found a script, that erases the grid and resets it on a page called "showing a map". I may need to work with that too.
I am also looking for a script to change the grid_fill, one room at a time, but have put that query into a separate post. I don't know if an answer to that even exists.

I like the idea of having a label somewhere that tells you what map level or "floor" you're on! When you discover it, please do share!

(new to quest and loving it)

You can create a start room, with no exits, with the label, I don't know, basement. Make one of the game start scripts move object player to (some other basement-room), a room with exits. Create a room up from the stairs with no exits, just the up entrance from the stairs. Label it ground floor or first floor. Make the "on entering room" script move object player to another room next to this. Make the way down lead to the game start room. This uses two stairways, but they can be one right next to the other.