Litang sounds good - I have never heard of this place, to be honest (but found this, which suggests it is not that "new" for tourists). More than 6000 USD for two per week sounds extremely expensive, I wonder if anyone's been to this area, and also whether you could simply arrange a car and a local guide in CTU or Litang...

Meili (xue) shan is not that much off the beaten track - I only know because some of my friends considered going hiking/climbing there (but eventually didn't). You could get a car from Deqen, and there are probably locals selling tours or rent huts/tents.