In reply to cwpkay:
For hiring kit:
In Aviemore Cairngorm Mountain Sports and Mountain Spirit both hire out the kit
In Braemar, Braemar Mountain Sports hire the kit
If you're travelling from the central belt Tiso Outdoor Experience just off the A9 outside Perth hire touring kit too.
You might want to experiment with getting the skins off/on before ending on on the Cairngorm plateau in a hoolie though.
Fingers crossed you get some decent weather.