I’ve been a bunch of times, with varying degrees of success! You can get away without a tripod if you have a steady hand. I have photos at ISO800 and 1/6s, and the noise isn’t too bad because there’s so much light around. There are also wooden handrails around the loch which you can perch the camera on for longer exposures.
That said, you’ll get better photos with a tripod 😉 Every time I’ve been, the forest/loch has been very sheltered so you don’t need a sturdy tripod or sandbag! Just set the 2s timer on the shutter (or use a remote) and you’ll be fine. I’d say use aperture priority, set ISO 400 (or less), aperture to f5 – 6.3 and you’ll probably get some longish exposures, depending what the camera’s deciding to meter for. If it’s windy, you can drop the aperture and/or bump the ISO to get much faster shutter speeds and avoid blurring of the trees.
Other than that, have fun, and show us your photos when you’re done! I’m going up next week and looking forward to it 🙂