I've dont the Frost River before and really loved Frost Lake.  We had low water when I did it and hated it (relatively speaking) !

Just returned yesterday from up that way.  Didn't do the Frost, but Paddle through Little Sag...Cool hole at the falls on the south East shore.

Best thing for you is that water levels werer awesome.  Water was high.  Quite frankly, some of the best water I've seen in years...so it should make the paddle throught the FR a ton better!  

Hope you have a great trip!