DISAPPOINTMENT = Your rental "car" company only has a Jeep !!
You were hoping for a Corolla and your disappointment affects the beginning of your trip. Then your attitude slowly adjusts to the inevitable and mouth corners accept the challenge as:
-the interweb tells you it's mileage is within 20% of your 19 year old ecomodded minivan (that has slightly smaller engine but much more luggage space)
-you internally give a sigh of relieve (Jeep not being known for fuel economy), then
-your Scan Gauge and internal gauges tell you that it gets better fuel economy than your old old beast, then
-the fillups verify better mileage, then
-you figure out how to get the most out of the "automatic" CVT -- push the shift lever to the side and it changes to manu-matic.
-Lock it into highest gear (6th) once you get high enough rpm to force/request 6th and only worry about shifting again when it forces you to downshift as you go below ? rpm
-determine what LOD forces the downshift (since we were in mountains) and
-realize that staying in 6th is more worthwhile than any other techniques so swooping through valleys and going fast when necessary in order to stay in 6th as long as possible is very successful (with this vehicle).
End result:
several thousand km over the Rockies and back average between 7 and 8 L/100km. If I can ever find the receipts I can post with more accuracy.