Respectfully disagree! I have had my TCH up to Canada on I-5 several times in winter and summer. Also down to California and on I-90 over to Idaho. It handles freeway speeds in the 80-90 range with no probelm, and is quiet, comfortable and roomy with an excellent stereo and AC. Plenty of power for passing trucks on climbs and for long climbs. In the California central vally, the temps were up above the hundreds, and the cabin environment was pleasant and cool.
True, FE drops from 44 down to 38 or even 36 at 90 MPH, but you can't have something for nothing. The only other downside is that a small amount of friction braking or downshifting was required for some of the steeper passes in Oregon. A true touring sedan might provide better handling for the mountain curves, but the TCH was more than adequate for the freeway radius curves and grade changes.
RFB
I quite agree. I just returned to Calif. from a 6 week tour into the mid-west. We went as far as SW Indiana. Within that distance the '06 Prius handled I-40, I-70, the US Hwys, state and county roads of Ks., Ne., and In. as the Prius was driven by my wife to support me in riding in Ks. and In.
This car has about 60,000 miles. It ran easily from speeds of 10-11, and sometimes as low as 5 mph as we followed clouds of cyclists on up to fwy speeds which I admit only exceeded 64 mph either in passing or a couple of down-hills.
Returning from Ks., we had our 23 yr old grand son shoe-horned into the seat behind the driver. The rest of the car was filled with a full size bike, it's wheels, 3 people's luggage. Well heck, all I could see rear view mirror was like a tunnel. I did make sure the vent to the battery pack was clear. Also made sure that the AC was blowing lots of cool air back there and over my grandson.
Temperatures ranged from the low 90's across Ks., Ok., Tx., NM., Az., and finally into Ca where the temp got up to 106.
Incedentley, I found little if any difference in the mpg because of having the crankcase a 1/2 qrt low or as usual over-filled by the dealer.
What's more I make this trek annually.
I never thought of the Prius as anything but a good all around sedan.
Oh, yes I too have had it up in Canada (Vancouver) and Toronto. But never in winter.