I rode the Glen Sligachan loop in April this year and it was immense. Although we did a lot of pushing after we turned off the road at Luib and waded through the edge of a Loch.
Therefore as others have recommended, do the out and back from the hotel and perhaps climb up towards the Am Mam pass (on the left when you reach Camasunary) and descend back down again.
The Quirang loop is great too but you may also find sections after the initial traverse boggy with plenty of slippy rocks thrown in. In fact the initial traverse might be something of an ar5e twitching experience in the wet as it’s a reasonably steep dropped in clipped in 🙂
One of the lads I rode the Quirang loop with spent a week up there and said the best ride he did started over near the Fairy Pools and had an amazing singletrack descent. Will try and track the e-mail down.
There is also a small trail centre/skills loop somewhere on the left just after you cross the bridge to Skye apparently.