If you need to fill a few hours, why not combine a number of smaller bushcraft tasks to achieve a bigger goal...
For example:
Tracking (could be set tracks) - to get them familiar with the surroundings;
Foraging (if no suitable foods, to find other resources, eg. firewood, nettles, etc)
Craftwork (eg. making cordage, carving butter knives / spoons, even just preparing feathersticks)
Firecraft (maybe working in groups to use a bowdrill, or using flint & steel / ferrocium rod)
Food prep. (ponassing fresh fish, or the likes)
Backwoods cooking (ready for meal-time)
Depending on location and whether there's time, you could also fit in a bit of shelter building or other activities.
None of these will seem monotanous in themselves and as they are conveyed as different activities they won't be too big a task, yet the result is an afternoon of 'bushcrafting'.
Hope this helps.