There aren't any official campsites around Glenbervie, but I'm sure you could arrange something for one night. Try MacPhies the local food processing company, the boss is the Laird for most of the land around Glenbervie. 01569 740641 They are very into community support. There is certainly the possibility for wild camping down near the river.
There was a caravan/camping site a bit further away towards Auchenblae at Brownmuir, but I have a feeling that it closed down for housing development, I'll check it out for you.
I could offer you a place if you can't find anything else but I'm a wee bit off your route, further along the Auchenblae to Stonehaven road toward Stoney.
My wife knows a lot of the local farmer's wives so if you just want to arrange something informal I'm sure she can help.

I'm guessing that you are planning on crossing the Mounth using either the Builg Mounth or Stockmount paths are you, they both come out of the Fetteresso forest at Chapelton?

I think that most challengers that come this way tend to spend their last night in the Forrest leaving them with a short day's walk to the coast on the last day.

Walking from Glenbervie to Catterline you are stuck with road walking along the maze of little country lanes which tend to be very quiet and not unpleasant. I suggest a route which minimises time spent walking along the A90, you can do this by using the old road for a while which is now an official footpath.

https://osmaps.ordnancesurvey.co.uk/route/1641535/Glenbervie-to-Catterline

You can take a look at it using Google Streetview.

Brian,

Thank you very much for the advice.

Not sure what I am doing yet- might settle for the route through Fetteresso and finish at Stoney, or might go slightly further east along the Deeside Way to Drumoak and cut south over Durris.

Gavin

OK, let me know if you need any local help.
Maybe this could be useful for you if you haven't seen it already.....

http://www.heritagepaths.co.uk/advancedResults.php?access=%23&type=%23&geo=8&x=14&y=10