Hello TamPepper,
The old wedge-shaped Churchyard at Balmerino has wide stone stairs linking 2 levels. Katherine's headstone is close to the row of yew trees on the higher level between the stairs & the yews. It faces & leans slightly forward towards the yews.
There's a car park & newer burial ground on the Kirkton side of the Churchyard but I've only come in from Balmerino. On the right, just past the ruins of Balmerino Abbey, a very narrow lane leads between the cottages to the Churchyard. There's a gate & space for 1-2 cars at the narrowest part of the wedge-shape on the Balmerino side. The lane goes on past the cemetery to the main car park & Kirkton village.
I found Katherine's headstone on a sunny day this summer (2015). The view from the Churchyard with the 'silvery Tay' sparkling in the sun was just perfect. A lovely place to have as your final resting place.
Regards, Dod.