My best full tank, mostly commuting and daily driving type stuff in my gasser Eco Cruze, was 50.93 MPG. I'll call it 51 MPG...
I just did some consumption vs. speed testing the other day. Two way average at 62 MPH was 53.9 MPG. Based on that, I would expect the Cruze TD to get at least 59 MPG in the same test. That's based on getting a multiplier from the Canadian hwy economy numbers and multiplying my result (4.6/4.2*53.9=59).