I ran General Grabber HTS which is low rolling resistance and pretty good in the snow (see recent consumer reports comparison) and quiet. This was my first tire on my Crd so no direct comparison of mileage. I did get 28 mpg cruising mostly 80+ mph through New Mexico and Arizona.
From my research, suv tires that are LRR are not much better than mild tread all terrains.
I think tire weight matters quite a bit also.
For towing, light four wheeling and good mileage I have decided on the Hankook Dynapro ATM. They are snow flake symbol branded (no chains required except extreme conditions) and lighter than virtually all other choices.
Do not get D or E rated tires if you want mileage and ride! Way too heavy.
I'll let you know if my mileage changes!
No question though, all tires are a compromise.
Good luck
Oh, and I have a Prius too! Also a Polaris Rzr as my hardcore off road toy. Used to rock crawl in a Samurai and a Cherokee like this: