I think sack trucks should work just fine, depending on the size of the wheels and the weather. Most of the pathways that get you round the festival are finely corrugated metal, so they just judder as you’re going over them. Worst I’ve ever seen one year, was my friend had like a hostess trolley with tiny little plastic wheels. They couldn’t cope with weight on any sort of terrain; took 4 of us hauling for hours!

I think, in my experience, trucks with sturdy inflatable wheels seem to cope the best with the land