I want to add a MGRS grid to each data driven page of a map book. Do I need to "make grid" for each page or is there a way to do it for the entire AOI and apply to each page? I also want to ensure that the border grid references are visible.
Have you tried adding one through the data frame properties rather than the GP tool? The former will create a dynamic grid with labels around whatever the current data frame extent shows as you navigate through the pages. It's more dynamic than the GP tool grids (which are created as features and annotation), but with less functionality and options to edit.
That appears as though it would work, but I have an added bit of complexity due to the area crossing two UTM zones. I was using the zone clipping template with the “make grid” tool to accomplish this. I do not know how to clean up the overlapping zones when using the data frame method you recommended.
Ah, yeah. The data frame grids don't have all of the options the GP tool grids have. They're different creatures, each with their own pros and cons.