It's in the Blairgowrie area - about 20 miles northish of Perth. A lovely part of the country.
Just turn up and run 53 miles - maybe not. I'm in the 8am start so only have 13 hours to complete - I guess that doesn't leave too much spare time for walking / lying down en route.
Last year on the Fling I was so enamoured by the tranquility of the loch that I went out and bought myself a canoe - it's quite tempting to not run and instead spend the day paddling up and down the section north of Inversnaid just watching the race...