Goukstone is a great base for walking in the area. You can follow the river Ythan through the wooded Gight Valley to the famous Gight Castle, once home to the Byron family but now a romantic ruin. Haddo House and Country Park is a great walk through the woods and with two cafés to choose from at Haddo, it’s a great spot to stop. If castles and stately homes are your thing, there are other great walks and Fyvie, Pitmedden and Tolquhon are all close by.
If you want to go a little further afield there are numerous excellent coastal walks ranging from dramatic rugged clifftop walks along the Buchan coast, home to Slains castle with connections to Bram Stokers' Dracula, to long beach walks at Newburgh (famous for its seal colony), Cruden Bay or Forvie Sands.
If you would rather take in the scenery from high above, the famous landmark of Bennachie is an excellent area to walk. There are numerous woodland walks accessible from the visitor centre and of course the trek to the summit rewards you with excellent views across the north east.