Elspeth - nearly forgot to suggest a run. If you want flat one with no navigation my favourite is getting on the canal SW to Dochgarroch, over the lock and back NE on the far side (a couple of muddy miles included) all the way to the sea lock on the Moray firth, over the lock and back to Bught Park via the newly graded gravel canal towpath. about 10 miles in total.
For a more adventurous run take the first 7km of this run:
http://connect.garmin.com/player/222008215
From Bught Park get on the canal going north, out to the sea loch, cross to the west side and back to Clachnaharry village. Take the road out of the village to the traffic light, left over the railway bridge, cross the road, go through the gap in the wall a few yards from the bridge. Climb the steep path to a cul-de-sac and continue up the concrete steps. Take a right on the road out of town until you see an obvious track going up into the woods on the left.
Take this for a steep climb through the woods in a generally southwards direction (there is a forest road or some footpath options, finding the iron age fort needs a map!). At Leachkin Brae go right up the very steep hill, and to make a better run than I did on 12/9 stay on the road until it flattens out, go past the nice house on the right and take the forest road on the right just beyond. This brings you to the Great Glen Way which will take you back to Bught Park. 8-9 miles with lots of climbing.