Hi Tommy
I completed the Cateran Trail approx 3 years ago. Booked through a company called Easyways who arranged the accommodation in advance.
Stayed at the following: Ivybank Guesthouse, Blairgowrie, Cruachan B&B in Kirkmichael (excellent food),
Dalhenzean Lodge - Spittal of Glenshee, The Glen Isla Hotel in Glen Isla and The Old Stables in Alyth. All have websites so you can arrange your own accommodation.
Also try the tourist information centre in Blairgowrie