I did this I think in 2011 (maybe 2010). I recall signs saying camping was prohibited at Beatty Lake, but obviously that has changed, and it did look like a great place to camp. I did the Beatty col 'route' (from Three Isle to Turbine), but I would advise against it. The views at the Col were nice, but the decent totally sucked. The initial descent was very steep and pretty sketchy, and there was no real route to speak of (unless I'm totally blind) so it was long and arduous. Finding the trail from there wasn't too bad, and it was in fair shape then IIRC.
Otherwise it was great! Be aware, definitely bear territory.