In a sheet view go to Ribbon > View > Guide Grid
Clicking this will prompt you to give a name to this particular Guide Grid for future reference and use in other Sheets.
After I click OK my entire Sheet will be covered with blue lines and become highly unreadable.
But that's fine for now. I'll just align the View to the Guide Grid by using the Ribbon > Modify > Move command. I am able to use Grids for this (as in my example), but Reference Planes will work as well (which can be handy if you don't have any - or too many - Grids).
OK, so now I know where I want to align the drawing on the sheet. Time to get rid of all those blue lines I don't need. I do this by selecing the Guide Grid and using the blue dots on the sides to make is just as big as really neccessary.
Time to create a second Sheet (or open it should you already have one created) and apply this Guide Grid. I do this in the View Properties of the Sheet.
I end up with this:
I now know that this one intersection of the Guide Grid is the one to which I need to align the intersection of Grids 1 and A of my 1st-floor drawing.
Oh, and don't worry. Revit will not plot the Guide Grid, so need to always turn it off again. (Although I find that it just looks nicer to not have it on. Call it a personal quirk.)