Which 300mm have you been using? Weights vary a fair bit, the basic 70-300 is around half a kilo, a 80-200 f2.8 about triple that.

There is also the 55-300vr. or even the 28-300vr FF. I guess it depends if you really need the 300mm, and if you are willing to carry more than one lens, and swap them around etc.

Where did you see the D7000 for $973?