My guess is the Archive resides in Milwaukee, it vanished for a reason in the Unseelie Incursion of 94, so if it was for the death of the current Archives grandmother leading to the birth of the current Archive in 1995 then Ivy would be 18- 19 by Battle Ground in 2014. Harry remarks at how grown up she looks.
Harry estimated Ivy as 12 - 13 in Ghost Story in 2012, but this is only his estimation and he is an unreliable narrator, so he could be several years off. This timeline would make her 16 when she dismissed Kincaid, when she could reach the pedals and drive herself.
Milwaukee would be a simple train journey for the Archive as presumably she is subject to the normal mortal wizard fudge factors ruling out air travel, and her neutrality ruling out travel via the Ways largely controlled by Winter and Summer. Nick would have taken this into account.