In reply to StefanB:
Hi Steff. I'm running, and did the HF in 2011 too.
I carried, and will do so this year, and small pack with some fluids and some food so I can keep nibbling through the race. There tends to be a mixture, lots of people will go light, but many (most?) will be carrying a small amount of kit.
The first section is flat and on a very good trail - easy to go away too fast (as I think I did in 2011). Over Conic Hill is a bit more rough, but not super-steep and fairly short-lived. After Rowardennan, along Loch Lomond all the way to Bein Glas is quite rough, undulating in places, and altogether quite slow. I found this very frustrating in 2011, and really slowed down. After Bein Glas its much more steady, slightly undulating and then downhill from above Crianlarich. The section from there to Tyndrum is, as you know, quite flat / fast (for me 'fast' is a relative term by that stage).
In my opinion the route generally is a bit tougher than that section, but there are plenty of easy sections.
Here's hoping for good weather (it was way too hot for me two years ago!).
I've never raced outside of the UK but I doubt you could do anything to offend anyone, in my experience these races are populated by a friendly bunch. One tip, mark your drop bags clearly, and say thanks to the marshalls.
I hope you have a great day.
Jamie.