Scotland Camping and "Bothies"

Doing a family trip to Scotland in June and after my parents and son take off, my brother and I will have four nights to do some camping.   We plan on hitting the Northwest Highlands (Ullapool, Glen Torridon, etc.) and want to check out a "bothy" or basic stone structure out on the moors where people can camp for free.

Anyone ever camp up in the Scottish Highlands or stay at a bothy?   Here is a website about them, but any first hand experiences with particular ones would be helpful:

http://www.mountainbothies.org.uk/bothies.asp

We will also have a van so we can always crash at the "caravan parks," but looking for something more rugged and off the beaten path and a remote bothy sounds perfect.