Hmmm, what can I say about 'doing' Cairngorm - apart from DON'T! Well at least wait till winter or until the Funicular Railway is built because at the moment (summer 2000) it looks like, no - it IS a building site and a complete mess! I hate to say that about a mountain in my country (and the fifth highest Munro) but its true. Or do it blindfolded....
But, should you still want to do it, the easiest way is from the Coire Cas car park where the ski lifts are. Drive down the road from Aviemore that takes you to Loch Morlich and Glenmore, and carry on till you see the signs! Park your car, marvel at how modern man can turn a beautiful, unique area into a disgusting tip then follow the scar, sorry landrover track up the mountain past the White Sheiling and up to the now defunct and derelict Ptarmigan Cafe. There you will see a nice neat path (yuk) which would not look out of place in Milton Keynes, going to your right. Follow it up by keeping your eyes on the length of blue polypropelyne rope that is allegedly a handrail until you see the first of a series of marker cairns. Follow them till you see a 15ft monster of a cairn and hey presto, thats the top! Now at this point I would tell you about the views, but seeing as the first time I did it there was low cloud and rain, and the second time I did it there was low cloud and rain - I may have to tell you about it another time. The only saving grace was the fact I had great company - I went with my dad!
I am sorry if it sounds all doom and gloom for Cairngorm - I really don't mean to put you off as there is so much around there that isnt scarred. You can take the Fiacaill Ridge Route from half way up the main route, which is a easy scramble though the fact you couldn't see your hand in front of your face because of low cloud prevented us from taking that route You can drop down to Loch Avon, cross to Ben Macdhui, Derry Cairngorm, Cairn Lochan and all the rest inc the Lairig Ghru and they are spectacular. And remember the building site is temporary. Like most hills Cairngorm would be best experienced in the winter - on a cold crisp day when theres a blanket of snow on the ground and I will certainly return then to banish a few ghosts.