In reply to Scarab: Pretty much everything worth climbing is in Scottish Rock. If nothing is particularly suitable, then basically you've picked the wrong part of the UK, as the Cairngorms is well down the list when it comes to really accessible, straightforward and high quality easier routes. I've taken novices out on several Cairngorm crags and won't be rushing back.
However, Western Buttress Route on Stac Pollaidh is a great route to take novices on, although it is a few hours further North.
That said for rigging top ropes Kinguissie Crag (in Highland Outcrops guidebook) is one of the better single pitch crags in the Central Highlands.